How To Split 2d Array In Python

This example list is incredibly useful, and we would like to get all the good examples and comments integrated in the official numpy documentation so that they are also shipped with numpy. While the answers above are more or less correct, you may run into trouble if the size of your array isn't divisible by 2, as the result of a / 2, a being odd, is a float in python 3. Here is what I have so far. How to Convert Dictionary Values to a List in Python Published: Tuesday 16 th May 2017 In Python, a dictionary is a built-in data type that can be used to store data in a way thats different from lists or arrays. The only difference between these functions is that array_split allows indices_or_sections to be an integer that does not equally divide the axis. How to Split a String on newlines in C#?. If True, return DataFrame/MultiIndex expanding dimensionality. NET List VB. I have a list a and need to convert it to a numpy array b with shape (2, 3, 4) and elements in the following order. NumPy: Array Object Exercise-61 with Solution. I am a newbie to Numpy module. Perl has a built-in function called sort that can, unsurprisingly, sort an array. An array is a set of values, which are termed elements, that are logically related to each other. Write a Python program to split an array of 14 elements into 3 arrays, each of which has 2, 4, and 8 elements in the original order. Related Articles. They serve to hold both sequences of characters and sequences of bytes. NumPy adds support for large, multi-dimensional arrays and matrices, along with an extensive collection of high-level mathematical functions to operate on these arrays. split() method or use of java. python , histogram , large-files if you only need to do this for a handful of points, you could do something like this. In the first example given by this problem, the first line of input that hackerrank automatically puts in when input() is called is '1 4' (which is converted to [1,4] using the split() and map() commands). A list is an ordered set of values, where each value is identified by an index. extend () method instead of the. Here I will show how to implement OpenCV functions and apply them in various aspects using some great examples. Can you please explain how the input to a and b variables are happening? As per the input in the problem n=2,the first two rows are inserted into a and why my doubt is how are the 3rd and 4th rows are iterated?. Python supports a special "array" from the array module. xarray: N-D labeled arrays and datasets in Python¶ xarray (formerly xray) is an open source project and Python package that makes working with labelled multi-dimensional arrays simple, efficient, and fun!. At some point, you may need to break a large string down into smaller chunks, or strings. The Python for statement iterates over the members of a sequence in order, executing the block each time. Parameters: m– input multi-channel array. Easiest way is to use the str. The boundary string. want to compare tow images using this method I was Install opencv and python using previous tutorial but i have problem with comparing the images. Python, read CSV file into 1D array, or 2D array into 1D array. Arrays are sequence types and behave very much like lists, except that the type of objects stored in them is constrained. loadtxt will split columns on white space but you can specify other separators using the delimiter keyword. String or regular expression to split on. Dictionaries are yet another kind of compound type. As per our typical word count example in Spark, RDD X is made up of individual lines/sentences which is distributed in various partitions, with the flatMap transformation we are extracting separate array of words from sentence. Python Forums on Bytes. Comparison with Python, similarity with JavaScript, are a few good ways you have used to attract programmers to try out some under-used things like bash arrays (particularly when bash is now available on almost every os, including windows). holding=[] # start a temp array for var in line. Here I will show how to implement OpenCV functions and apply them in various aspects using some great examples. You now need to use Python's built-in string method called. So, let's quickly import it!. Python: Split string method and examples How to split string in Python So you are looking to break up a string into smaller strings (into an array if you are coming from a PHP / JavaScript background) based on a delimiter or character. Then sum them. array — Efficient arrays of numeric values¶ This module defines an object type which can compactly represent an array of basic values: characters, integers, floating point numbers. For example, you can add a 16-bit unsigned array to a 8-bit signed array and store the sum as a 32-bit floating-point array. Thus all available cores are used simultaneously enabling computations on arrays which are larger than the memory size. I would like to split a 2D array into two separated 2D arrays on provided conditions. It contains among other things: a powerful N-dimensional array object. I guess you are thinking that I am a python expert. split method which can be used. Before making this change, keep in mind that there are fundamental differences between lists and sets. array_split Split an array into multiple sub-arrays of equal or near-equal size. I take a space delimited string and split it into a List then I join the list back into a space delimited, then comma delimited string Python split and join strings to arrays and back george. view_as_windows, which sub-divide a multi-dimensional array into a number of multi-dimensional sub-arrays (slices). Perhaps theoretically/under the hood that is correct however a major distinction between the two is the fact that lists accept mixed data types and mixed numeric types, on the other hand array requires a type-code restricting all elements to the determined type:. You are probably better off using the python csv module. This tutorial will give a detailed introduction to CSV’s and the modules and classes available for reading and writing data to CSV files. Given a nested 2D list, the task is to split the nested list into two lists such that first list contains first elements of each sublists and second list contains second element of each sublists. Reshape a 2D array of size m x n into a 1D array of length mn, then do the inverse procedure and get it back to a 2D m x n array. Once Python has created a tuple in memory, it cannot be changed. Generally, I'm dealing with a byte stream that I want to output as a string of hex. read_csv('test. When we talk about hash tables, we're actually talking about dictionary. Updated for Python 3. Python has an amazing feature just for that called slicing. NumPy is the library that gives Python its ability to work with data at speed. A CSV file is a human readable text file where each line has a number of fields, separated by commas or some other delimiter. I run array = {} Then, I try to add something to this array by doing: array. Python Forums on Bytes. That can be useful if you want to skip a text column. Documentation: Python: cv2. In our last python tutorial, we studied How to Work with Relational Database with Python. You see the. Reading CSV files using Python 3 is what you will learn in this article. The first argument is the name of a user-defined function, and second is iterable like a list, string, set, tuple, etc. array_split Split an array into multiple sub-arrays of equal or near-equal size. In Python, data is almost universally represented as NumPy arrays. The first one is O (len (s)) (for every element in s add it to the new set, if not in t). NumPy Array Object Exercises, Practice and Solution: Write a NumPy program to split of an array of shape 4x4 it into two arrays along the second axis. How do i input into an array in Python? I'm making a binary to decimal converter and I want my input to be split into separate parts of the array So if I input 1101 I want array=[1,1,0,1]. How to use Split in Python. Then you can use the. To construct the new tuple, it is convenient that we can slice parts of the old tuple and. The best way we learn anything is by practice and exercise questions. You need to parse your file line by line: import json data = [] with open (. The programming language Python makes it relatively easy to step, or loop, through the elements of a list and compute some property for each of them. This article describes how to write a list to file, and how to read that list back into memory. As serialized data structures, Python programmers intensively use arrays, lists, and dictionaries. Sometimes you will be working NumPy arrays and may still want to perform groupby operations on the array. Isn't train_test_split expecting both X and Y to be a list of same length? Your X has length of 6 and Y has length of 29. How To Reverse Each Word Of A String In Java? Split the given inputString into words using split() method. 4) Read string char by char, copy to another string, with a condition/statement that put splitter character (a marker) after every two char read, and then split string. A matrix is a two-dimensional data structure where numbers are arranged into rows and columns. Python, Perl and Golang. But anyway, thanks for the explanation and for the work you do. Then you can use the. So care must be taken as to which is preferred, depending on which one is the longest set and whether a new set is needed. We can create a flattened 2D array. The best way we learn anything is by practice and exercise questions. n: int, default -1 (all) Limit number of splits in output. Note that the list can be of arbitrary depth and may not have a regular shape, and will contain arrays of differing dimensions. What I wanted was plyr for Python! Sadly, it does not yet exist, but I used a hacky solution from the multiprocessing package for a while. Most of the data structures make use of arrays to implemen. Visually, you can represent a NumPy array as something like this: This is a visual representation of a NumPy array that contains five values: 88 , 19 , 46 , 74 , 94. home > topics > python > questions > how to import array from a file arrays. Can anyone solve this in python? write a program which prints the sum of the elements of array A with the corresponding elements of the reverse of array A. We will use the term element or item to mean the same thing. In this tutorial, we will understand the Python arrays with few examples. to split a 1D list up in pieces, use slice notation. I have each line of the text file saved as an array. In this exercise you can learn how to split and combine NumPy arrays. First we’ll create a List object that will store parts of the split string. Using NumPy's numpy. We just want to add new array elements at the end of the array. Expand the splitted strings into separate columns. A NumPy tutorial for beginners in which you'll learn how to create a NumPy array, use broadcasting, access values, manipulate arrays, and much more. There are splitting functions in numpy. sample() function returns a k length list of unique elements chosen from the population sequence or set, used for random sampling without replacement. Hi everyone! After my last post on linear regression in Python, I thought it would only be natural to write a post about Train/Test Split and Cross Validation. Arrays in Visual Basic. July 6, 2013 ⌛ Tagged With: python To extract frequent words from some text we can work with Dict in Python. Write a java program to reverse each word of a given string? For example, If “Java Concept Of The Day” is input string then output should be “avaJ tpecnoC fO ehT yaD”. array(a) # a is input list out = np. Python arrays are powerful, but they can confuse programmers familiar with other languages. With these methods we can handle CSV files (comma-separated values). None, 0 and -1 will be interpreted as return all splits. It's nearly there already, it simply needs to throw away duplicate results when concatenating the child arrays (easy to do when the child arrays are guaranteed in-order and unique), and because it's a divide and conquer algorithm it should lend itself to a parallel environment. Can anyone solve this in python? write a program which prints the sum of the elements of array A with the corresponding elements of the reverse of array A. Making Your First Foreach Loop in Python If you’ve ever used a standard foreach loop, a Python loop may seem a little strange. The last character has index -1, the second to last character has index -2. This article describes how to write a list to file, and how to read that list back into memory. This post shows you how to plot polygons in Python. Can you please explain how the input to a and b variables are happening? As per the input in the problem n=2,the first two rows are inserted into a and why my doubt is how are the 3rd and 4th rows are iterated?. You can look into Numpy Arrays vs Lists to know more. Therefore, when we talk about python arrays, we usually mean python lists. However, python does provide Numpy Arrays which are a grid of values used in Data Science. Arrays (Lists) First of all, bear in mind that Python is calling the thing that I knew as an 'array' in MEL, a 'list'--so if you go to Python. split The string split() method breaks a given string around matches of the given regular expression. Note that numpy. a = "We are Edureka, we have cutting edge tutorials and certification programs to upskill your knowledge" print(a. split(): This function Split an array into multiple sub-arrays. You can help. List can store only one type of objects, that type supplied as its generic parameter. indices_or_sections : int or 1-D array If indices_or_sections is an integer, N, the array will be divided into N equal arrays along axis. A couple of contributions suggested that arrays in python are represented by lists. Python: Split string method and examples How to split string in Python So you are looking to break up a string into smaller strings (into an array if you are coming from a PHP / JavaScript background) based on a delimiter or character. Arrays in Python is an altogether different thing. This post will be helpful in learning OpenCV using Python programming. We divide based on a delimiter character—here we use a single comma. In practice you wont implement linear regression on the entire data set, you will have to split the data sets into training and test data sets. It provides a high-performance multidimensional array object, and tools for working with these arrays. Like many other popular programming languages, strings in Python are arrays of bytes representing unicode characters. 666667 Name: ounces, dtype: float64 #calc. py supports these functions, even though in most cases you would want to use Python built. NumPy's concatenate function allows you to concatenate two arrays either by rows or by columns. If it is not provided then there is no limit. Slicing in Python When you want to extract part of a string, or some part of a list, you use a slice The first character in string x would be x[0] and the nth character would be at x[n-1]. Machine learning data is represented as arrays. The boundary string. Resulting text files are stored in the same directory as the original file. append method for this. Split a 2D array of size 2 x N into two 1D arrays of length N. The programmer can access the data stored at at particular address within the list, as well as removing data stored at a particular address. This page gives a basic introduction to regular expressions themselves sufficient for our Python exercises and shows how regular expressions work in Python. split() work on the original string, not on the list result of the first call to. $ python array_string. Within this loop convert each element of the string array to integer and assign to the array created in the previous step. However one must know the differences between these ways because they can create complications in code that can be very difficult to trace out. In this tutorial, you will discover how to. Strings are immutable. - [Narrator] File Open when you're creating arrays from Python Structures File, by clicking on its file name. Just like the str() built-in, Python also offers a handy built-in which takes a string object as an argument and returns the corresponding integer object. Total number of sub-arrays (with optional per-axis number of sections constraints). In most situations it is more convenient to work with the underlying grid (i. Using String. Python String split is commonly used to extract a specific value or text from a given string. regex package is. None, 0 and -1 will be interpreted as return all splits. For example, suppose you want to print only the positive. append method for this. This book contains 100 recipes that teach you how to perform various machine learning tasks in the real world. I found myself wanting to flatten an array of arrays while writing some Python code earlier this afternoon and being lazy my first attempt involved building the flattened array manually:. I could get the chunks off of the data set with chunksize set to 500,000 rows and process the computation of the R-Squared score on the training/test split data sets in each iteration of 500,000 rows till iteration #20. The array_split python package is an enhancement to existing numpy. Hi, I have generated an array of random numbers and I'm trying to then write this array to a. Allows duplicate members. Learn to join or split arrays NumPy arrays in this video tutorial by Charles Kelly. The basics of slicing 1- and 2-dimensional NumPy arrays. Python has a method to search for an element in an array, known as index(). each row and column has a fixed number of values, complicated ways of subsetting become very easy. For example, reading a CSV file line and parsing them to get all the data to a String array. There are two variants of split() method in Java:. By default, this method will split a string into parts separated by a space. NumPy arrays are a structure in Python that hold numerical values that are all of the same type. Matplotlib histogram is used to visualize the frequency distribution of numeric array by splitting it to small equal-sized bins. For example, an array may consist of the number of students in each grade in a grammar school; each element of the array is the number of students in a single grade. Perl has a built-in function called sort that can, unsurprisingly, sort an array. I already created an array with zeros, but I don't know how to fill it with the data from the csv file. The string splits at this specified separator. Once Python has created a tuple in memory, it cannot be changed. Please refer to the split documentation. For example. useful linear algebra, Fourier transform, and random number capabilities. When one or more of the arrays to be concatenated is a MaskedArray, this function will return a MaskedArray object instead of an ndarray, but the input masks are not preserved. NET arrays can be indexed and iterated over as if they were Python lists:. Ironically only a few days later I found myself in a situation where I needed to do the exact opposite task and split a large csv file into smaller chunks. A list is an ordered set of values, where each value is identified by an index. NumPy is a Python package providing fast, flexible, and expressive data structures designed to make working with 'relationa' or 'labeled' data both easy and intuitive. array_split Split an array into multiple sub-arrays of equal or near-equal size. a = [1, 3, 4]). The array_split package provides the means to partition an array (or array shape) using any of the following criteria: Per-axis indices indicating the cut positions. At some point, you may need to break a large string down into smaller chunks, or strings. With join, we combine a string list into a single string separated with a comma char. How to use Split in Python At some point, you may need to break a large string down into smaller chunks, or strings. array — Efficient arrays of numeric values¶ This module defines an object type which can compactly represent an array of basic values: characters, integers, floating point numbers. A dictionary in Python is really an associative array or hash table that is composed of key-value pairs. split The string split() method breaks a given string around matches of the given regular expression. Python, Perl and Golang. Learn how to split array using Python numpy. Does not raise an exception if an equal division cannot be made. Slicing in Python When you want to extract part of a string, or some part of a list, you use a slice The first character in string x would be x[0] and the nth character would be at x[n-1]. NumPy Array Object Exercises, Practice and Solution: Write a NumPy program to split of an array of shape 4x4 it into two arrays along the second axis. How to Perform Sentiment Analysis in Python Step 1: Create a new Python file, and import the following packages:. Given a nested 2D list, the task is to split the nested list into two lists such that first list contains first elements of each sublists and second list contains second element of each sublists. Sometimes you will be working NumPy arrays and may still want to perform groupby operations on the array. For convience, lets call them arrays in this article. reshape(-1,8000,1) Split into train and validation set. There are numerous methods available with the string object. Also, arrays support many of the same methods as regular lists. We store a list into an array the same way we store a scalar into a scalar variable, by assigning it with =: for a tuple, or for a list. You will learn to declare, initialize and access array elements of an array with the help of examples. Notes # Arrays in Python are an altogether different beast compared to PHP or JavaScript. Slicing Python Lists/Arrays and Tuples Syntax. There are multiple functions and ways of splitting the numpy arrays, but two specific functions which help in splitting the NumPy arrays row wise and column wise are split and hsplit. Thus all available cores are used simultaneously enabling computations on arrays which are larger than the memory size. They are somewhat confusing, so we examine some examples. As serialized data structures, Python programmers intensively use arrays, lists, and dictionaries. - Know how to use matplotlib and seaborn libraries to create beautiful data visualization. This post shows you how to plot polygons in Python. Both can contain multiple values, but only a list can contain duplicate values -- a set cannot. tools for integrating C/C++ and Fortran code. Python includes a variety of types of loop, including "while" loops that continue until a condition is no longer true and "for" loops that execute code once on each element of a list. Learn to join or split arrays NumPy arrays in this video tutorial by Charles Kelly. When appending it to another list, you get the list of lists. Create a new 8x8 array with some values (or continue with the one created in Step 2. Write a Python program to split an array of 14 elements into 3 arrays, each of which has 2, 4, and 8 elements in the original order. If array A has elements [1,2,3], then reverse of the array A will be [3,2,1] and the resultant array should be [4,4,4]. 0 and VBA Split() function, described here. a = array ( "i" ) # Append three integers. So like strings, tuples are immutable. Next, you have to combine the data and the class labels, and for that, you will use an excellent python library called NumPy. The hash code is then used to calculate a location in an internal array where the value will be stored. The core built-in types for manipulating binary data are bytes and bytearray. 1BestCsharp blog 5,654,715 views. Note that contrary to the previous solution, boost::split will provide an empty string as a last element of results if the input string ends with a delimiter. The first argument is the name of a user-defined function, and second is iterable like a list, string, set, tuple, etc. That's all on how to print array values in Java. The array will be divided in to parts with nearly equal size. In this Python NumPy tutorial, we will be introducing various aspects of NumPy Python, such as how to do data analysis with NumPy Python, creating arrays in NumPy Python, operations on NumPy Python arrays, NumPy Python array methods, array comparison and filtering, how to reshape NumPy Python arrays, and more. Nesting is a useful feature in Python, but sometimes the indexing conventions can get a little confusing so let’s clarify the process expanding from our courses on Applied Data Science with Python We will review concepts of nesting lists to create 1, 2, 3 and 4-dimensional lists, then we will convert them to numpy arrays. Second, you cannot omit the $ if you're using a parameter as the key of an associative array. Python Classes/Objects. In this article we are going to see how we can sort an array of strings or numbers in Perl. Strings, Lists, Arrays, and Dictionaries¶ The most import data structure for scientific computing in Python is the NumPy array. Using this information, we can use Python's array functionality, called "slicing", on our strings! Slicing is a general piece of functionality that can be applied to any array-type object in Python. Python passing parameters by reference. And then create your own: how about odd numbers counting backwards on the first row, and even numbers on the second? Use the functions len(), numpy. Join and split strings. Welcome to Google's Python Class -- this is a free class for people with a little bit of programming experience who want to learn Python. split(): This function Split an array into multiple sub-arrays. For example: For loop from 0 to 2, therefore running 3 times. sophisticated (broadcasting) functions. As in real life, before you can do anything with a list, you must create it. A dictionary in Python is really an associative array or hash table that is composed of key-value pairs. The topic is very important and is part of class XII Course. Just as strings are defined as characters between quotes, lists are defined by having values between square brackets [ ]. Python program that uses append, insert, remove, count from array import array # New int array. A string in Python is a sequence of characters. We are going to follow the below workflow for implementing the logistic regression model. Why Python? Frequently, you will want to do perform a relatively simple task with you computer, but, the task will be extremely cumbersome or impossible to do with c-shell, and you will dread spending all the time to write a full blown c program. how to use formed arrays when integrating ODEINT Posted 23 May 2017 - 10:20 AM have a problem with my physics task, but you do not need to understand physics to be able to help me, because my main problem is bad programming skill. If you are new to Python, you may be confused by some of the pythonic ways of accessing data, such as negative indexing and array slicing. - Know how to create and manipulate arrays using numpy and Python. NumPy is the library that gives Python its ability to work with data at speed. python Programming Guide. That means, if you apply a function it is performed on every item in the array, rather than on the whole array object. To construct the new tuple, it is convenient that we can slice parts of the old tuple and. - Have an amazing portfolio of example python data analysis projects!. If you import X from your main program, Python will load the code for X and execute it. 666667 Name: ounces, dtype: float64 #calc. The programming language Python makes it relatively easy to step, or loop, through the elements of a list and compute some property for each of them. Python Forums on Bytes. concatenate(). How are arrays defined and used in python? So we all know arrays are not present as a separate object in python but we can use list object to define and use it as an array. split REGEX, STRING will split the STRING at every match of the REGEX. You can help. python Programming Guide. Implode and explode is the basic operation in any programming language. 4): The results are the same as the above. split() work on the original string, not on the list result of the first call to. How to Convert Dictionary Values to a List in Python Published: Tuesday 16 th May 2017 In Python, a dictionary is a built-in data type that can be used to store data in a way thats different from lists or arrays. In this article, we show how to create an empty dictionary in Python. In this exercise, baseball is a list of lists. This overloading of purpose leads to confusion and bugs. After you create a list using Python, you want to access the information it contains. concatenate Join a sequence of arrays along an existing axis. The post will offer simple solutions, easy-to-follow and straightforward explanations and some tips and tricks that you can practice on the spot with the help of some. Split the data into training and test dataset. How and when do I use for loops under Python programming language? A for loop is a Python statement which repeats a group of statements a specified number of times. It does that by returning a list of the resulting sub-strings (minus the delimiters). split function is used for Row wise splitting. How to parse key-value strings into associative arrays in ANSI C89 We all know that C is one of the best languages for many reasons and especially the ANSI C89 standard (old and solid as fuck) but it also has it’s own drawbacks. So far, I am able to make the program print out the numbers as a 2d array. By comparison an array is an ordered collection of items of a single type - so in principle a list is more flexible than an array but it is this flexibility that makes things slightly harder when you want to work with a regular structure. xarray: N-D labeled arrays and datasets xarray (formerly xray ) is an open source project and Python package that makes working with labelled multi-dimensional arrays simple, efficient, and fun! Xarray introduces labels in the form of dimensions, coordinates and attributes on top of raw NumPy -like arrays, which allows for a more intuitive. Arrays are often implemented via lists, the 2D arrays can be implemented via lists of lists. n: int, default -1 (all) Limit number of splits in output. array_split¶ numpy. PHP’s arrays are very versatile, but in Python, you need to think in terms of lists and dictionaries. NET (c#) that has a new line character? Below is a sample code snippet that demonstrates how to do it. Given a nested 2D list, the task is to split the nested list into two lists such that first list contains first elements of each sublists and second list contains second element of each sublists. Python has a built-in string class named "str" with many handy features (there is an older module named "string" which you should not use). append method for this. AWK was the first language I found that has associative arrays. NumPy: Array Object Exercise-61 with Solution. Create a simple two dimensional array. split(','): # for each value append it to the temp array holding. String or regular expression to split on. Python: histogram/ binning data from 2 arrays. The topic is very important and is part of class XII Course. After you create a list using Python, you want to access the information it contains. However, when you work with CSV files in Python, you should instead use the csv module included in Python's standard library. append () at the line 5. • List is a collection, which is ordered and changeable. The first index, if omitted, defaults to 0, so that your chunk starts from the beginning of the original string; the second defaults to the highest position in the string, so that your chunk ends at the end of the original string. The opposite operation is to extract the rows or columns of a 2D array into smaller arrays. You can use an array literal. In its most simple form, you just give it an array, and it returns the elements of that array in a sorted order. Hi everyone! After my last post on linear regression in Python, I thought it would only be natural to write a post about Train/Test Split and Cross Validation. This section will present several examples of using NumPy array manipulation to access data and subarrays, and to split, reshape, and join the arrays. Although arrays are often more practical for storing data, in situations where a key-value pair is preferred for working with data (with properties acting as the "key"), there may be instances where you want to check if any of those keys hold a particular value. Python has an amazing feature just for that called slicing. An array is a variable that can store multiple values. Dictionaries¶ All of the compound data types we have studied in detail so far — strings, lists, and tuples — are sequence types, which use integers as indices to access the values they contain within them. concatenate function from the masked array module instead. The best way we learn anything is by practice and exercise questions. Note that contrary to the previous solution, boost::split will provide an empty string as a last element of results if the input string ends with a delimiter. Arrays are usually referred to as lists. Python Forums on Bytes. The fact-checkers, whose work is more and more important for those who prefer facts over lies, police the line between fact and falsehood on a day-to-day basis, and do a great job. Today, my small contribution is to pass along a very good overview that reflects on one of Trump’s favorite overarching falsehoods. Namely: Trump describes an America in which everything was going down the tubes under  Obama, which is why we needed Trump to make America great again. And he claims that this project has come to fruition, with America setting records for prosperity under his leadership and guidance. “Obama bad; Trump good” is pretty much his analysis in all areas and measurement of U.S. activity, especially economically. Even if this were true, it would reflect poorly on Trump’s character, but it has the added problem of being false, a big lie made up of many small ones. Personally, I don’t assume that all economic measurements directly reflect the leadership of whoever occupies the Oval Office, nor am I smart enough to figure out what causes what in the economy. But the idea that presidents get the credit or the blame for the economy during their tenure is a political fact of life. Trump, in his adorable, immodest mendacity, not only claims credit for everything good that happens in the economy, but tells people, literally and specifically, that they have to vote for him even if they hate him, because without his guidance, their 401(k) accounts “will go down the tubes.” That would be offensive even if it were true, but it is utterly false. The stock market has been on a 10-year run of steady gains that began in 2009, the year Barack Obama was inaugurated. But why would anyone care about that? It’s only an unarguable, stubborn fact. Still, speaking of facts, there are so many measurements and indicators of how the economy is doing, that those not committed to an honest investigation can find evidence for whatever they want to believe. Trump and his most committed followers want to believe that everything was terrible under Barack Obama and great under Trump. That’s baloney. Anyone who believes that believes something false. And a series of charts and graphs published Monday in the Washington Post and explained by Economics Correspondent Heather Long provides the data that tells the tale. The details are complicated. Click through to the link above and you’ll learn much. But the overview is pretty simply this: The U.S. economy had a major meltdown in the last year of the George W. Bush presidency. Again, I’m not smart enough to know how much of this was Bush’s “fault.” But he had been in office for six years when the trouble started. So, if it’s ever reasonable to hold a president accountable for the performance of the economy, the timeline is bad for Bush. GDP growth went negative. Job growth fell sharply and then went negative. Median household income shrank. The Dow Jones Industrial Average dropped by more than 5,000 points! U.S. manufacturing output plunged, as did average home values, as did average hourly wages, as did measures of consumer confidence and most other indicators of economic health. (Backup for that is contained in the Post piece I linked to above.) Barack Obama inherited that mess of falling numbers, which continued during his first year in office, 2009, as he put in place policies designed to turn it around. By 2010, Obama’s second year, pretty much all of the negative numbers had turned positive. By the time Obama was up for reelection in 2012, all of them were headed in the right direction, which is certainly among the reasons voters gave him a second term by a solid (not landslide) margin. Basically, all of those good numbers continued throughout the second Obama term. The U.S. GDP, probably the single best measure of how the economy is doing, grew by 2.9 percent in 2015, which was Obama’s seventh year in office and was the best GDP growth number since before the crash of the late Bush years. GDP growth slowed to 1.6 percent in 2016, which may have been among the indicators that supported Trump’s campaign-year argument that everything was going to hell and only he could fix it. During the first year of Trump, GDP growth grew to 2.4 percent, which is decent but not great and anyway, a reasonable person would acknowledge that — to the degree that economic performance is to the credit or blame of the president — the performance in the first year of a new president is a mixture of the old and new policies. In Trump’s second year, 2018, the GDP grew 2.9 percent, equaling Obama’s best year, and so far in 2019, the growth rate has fallen to 2.1 percent, a mediocre number and a decline for which Trump presumably accepts no responsibility and blames either Nancy Pelosi, Ilhan Omar or, if he can swing it, Barack Obama. I suppose it’s natural for a president to want to take credit for everything good that happens on his (or someday her) watch, but not the blame for anything bad. Trump is more blatant about this than most. If we judge by his bad but remarkably steady approval ratings (today, according to the average maintained by 538.com, it’s 41.9 approval/ 53.7 disapproval) the pretty-good economy is not winning him new supporters, nor is his constant exaggeration of his accomplishments costing him many old ones). I already offered it above, but the full Washington Post workup of these numbers, and commentary/explanation by economics correspondent Heather Long, are here. On a related matter, if you care about what used to be called fiscal conservatism, which is the belief that federal debt and deficit matter, here’s a New York Times analysis, based on Congressional Budget Office data, suggesting that the annual budget deficit (that’s the amount the government borrows every year reflecting that amount by which federal spending exceeds revenues) which fell steadily during the Obama years, from a peak of $1.4 trillion at the beginning of the Obama administration, to $585 billion in 2016 (Obama’s last year in office), will be back up to $960 billion this fiscal year, and back over $1 trillion in 2020. (Here’s the New York Times piece detailing those numbers.) Trump is currently floating various tax cuts for the rich and the poor that will presumably worsen those projections, if passed. As the Times piece reported: