How to Read Every Word in File Python

Opening a file and reading the content of a file is ane of the common things you would do while doing data analysis.

In this tutorial, we will see iii examples of reading a text file in Python three.

One piece of cake way to read a text file and parse each line is to utilize the python statement "readlines" on a file object.

How To Read all lines in a file at one time? Use readlines()

If y'all want to read all lines of a file at the same time, Python'south readlines() function is for you. Python's readlines function reads everything in the text file and has them in a listing of lines. Here is an instance of how to use Python's readlines.

We first open up the file using open() part in read only mode. And apply the file handler from opening the file to read all lines using readlines() as follows.

# Open the file with read only permit f = open up('my_text_file.txt', "r") # use readlines to read all lines in the file # The variable "lines" is a list containing all lines in the file lines = f.readlines() # close the file after reading the lines. f.close()          

We can also read all the lines of a file at once in some other way. Basically, we would utilise the file handler object after opening the file as argument to listing() function to become all the lines equally a listing.

Another way to read lines at in one case is to simply use

# read all lines at once lines = list(f)          

Note that the last graphic symbol of each line is newline grapheme.

So you tin can go over the list of "lines" to parse each line. Every bit you tin can immediately find, "readlines" or "list(f) works great for a small text file. All the same, it is not retention efficient to use if your text files are really big. A ameliorate way to read a text file that is retention-friendly is to read the file line past line, that is one line at a time.

Core Python has (at to the lowest degree) two means to read a text file line by line easily.

How To Read a Text File Line past Line Using While Argument in Python?

Here is the way to read text file i line at a time using "While" statement and python's readline function. Since we read one line at a time with readline, we can easily handle big files without worrying most memory problems.

# Open the file with read only permit f = open('my_text_file.txt') # use readline() to read the showtime line  line = f.readline() # use the read line to read further. # If the file is not empty keep reading i line # at a fourth dimension, till the file is empty while line:     # in python 2+     # print line     # in python 3 print is a builtin office, so     print(line)     # use realine() to read side by side line     line = f.readline() f.close()          

Another variation of reading a file with while statement and readline statement is every bit follows. Here the while tests for boolean and read line past line until we reach the finish of file and line volition be empty.

# file handle fh fh = open up('my_text_file.txt') while True:     # read line     line = fh.readline()     # in python 2, print line     # in python 3     print(line)     # bank check if line is not empty     if not line:         intermission fh.close()          

How To Read a Text File Line by Line Using an Iterator in Python?

One can also utilize an iterator to read a text file 1 line at time. Here is how to do information technology.

fh = open up('my_text_file.txt') for line in fh:     # in python 2     # print line     # in python three     impress(line) fh.close()          

Remembering to close the file handler ("fh") with the statement "fh.close()" can be difficult initially. One tin check if a file handler is closed with

# check if the file file handler is airtight or not >fh.closed # true if the file handler is closed  Truthful          

One can open files in a much simpler way using "with" statement in Python, without having to close the file handler. The with operator creates a context director and it will automatically close the file for you lot when you lot are done with information technology.

Check here to see how to utilise "with" statement to open up file.

• "with" argument in Python to Open up a file

Do you want to read a text file line by line and skip comment lines?, check this mail

• 3 Ways to Read a File and Skip Initial Comment lines in Python

Exercise you want to read/load text file numerical data, check this post

• How to read a numerical data/file in Python with numpy?

Do you lot have data in a csv or tab express text file and want to read it in Python? The best selection is to use Python's pandas bundle. Here is how to load information files in python with Pandas,

• 7 Tips to Read a CSV File as Pandas Information Frame

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Source: https://cmdlinetips.com/2011/08/three-ways-to-read-a-text-file-line-by-line-in-python/

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