Python Read the First Letter of Line of File
Summary: in this tutorial, yous learn various means to read text files in Python.
TL;DR
The following shows how to read all texts from the readme.txt file into a cord:
with open up('readme.txt') as f: lines = f.readlines()
Code linguistic communication: JavaScript ( javascript ) Steps for reading a text file in Python
To read a text file in Python, you lot follow these steps:
- First, open a text file for reading by using the
open()function. - Second, read text from the text file using the file
read(),readline(), orreadlines()method of the file object. - Third, close the file using the file
close()method.
one) open up() function
The open() function has many parameters merely you'll be focusing on the first ii.
open(path_to_file, mode)
The path_to_file parameter specifies the path to the text file.
If the file is in the same folder equally the program, you just need to specify the proper name of the file. Otherwise, yous demand to specify the path to the file.
To specify the path to the file, you utilize the frontwards-slash ('/') even if you're working in Windows.
For example, if the file is readme.txt stored in the sample folder as the program, you lot need to specify the path to the file as c:/sample/readme.txt
The mode is an optional parameter. It's a cord that specifies the fashion in which you lot want to open up the file.
The post-obit tabular array shows available modes for opening a text file:
| Mode | Clarification |
|---|---|
'r' | Open for text file for reading text |
'w' | Open a text file for writing text |
'a' | Open a text file for appending text |
For example, to open a file whose name is the-zen-of-python.txt stored in the same binder equally the plan, you use the following lawmaking:
f = open('the-zen-of-python.txt','r')
Code language: JavaScript ( javascript ) The open() part returns a file object which you will use to read text from a text file.
2) Reading text methods
The file object provides you with iii methods for reading text from a text file:
-
read()– read all text from a file into a string. This method is useful if you have a small file and yous want to manipulate the whole text of that file. -
readline()– read the text file line by line and render all the lines as strings. -
readlines()– read all the lines of the text file and return them as a list of strings.
three) close() method
The file that you open volition remain open until you lot close it using the close() method.
It'south important to close the file that is no longer in use. If y'all don't close the file, the plan may crash or the file would be corrupted.
The following shows how to telephone call the close() method to shut the file:
f .close()
Code language: CSS ( css ) To shut the file automatically without calling the close() method, y'all use the with statement like this:
with open(path_to_file) as f: contents = f.readlines()
Code language: JavaScript ( javascript ) In practise, you'll apply the with statement to close the file automatically.
Reading a text file examples
We'll use the-zen-of-python.txt file for the demonstration.
The following example illustrates how to utilize the read() method to read all the contents of the the-zen-of-python.txt file into a string:
with open('the-zen-of-python.txt') equally f: contents = f.read() print(contents)
Code language: JavaScript ( javascript ) Output:
Beautiful is better than ugly. Explicit is improve than implicit. Uncomplicated is improve than complex. ...
The post-obit case uses the readlines() method to read the text file and returns the file contents every bit a list of strings:
lines = [] with open('the-zen-of-python.txt') as f: lines = f.readlines() count = 0 for line in lines: count += 1 impress(f'line {count}: {line}')
Code linguistic communication: JavaScript ( javascript ) Output:
line 1: Beautiful is better than ugly. line 2: Explicit is better than implicit. line 3: Elementary is amend than complex. ...
The following example shows how to use the readline() to read the text file line by line:
with open('the-zen-of-python.txt') as f: line = f.readline() while line: line = f.readline() print(line)
Code language: JavaScript ( javascript ) Output:
Explicit is improve than implicit. Elementary is better than complex. Circuitous is meliorate than complicated. ...
A more concise fashion to read a text file line by line
The open up() part returns a file object which is an iterable object. Therefore, y'all can apply a for loop to iterate over the lines of a text file as follows:
with open up('the-zen-of-python.txt') as f: for line in f: print(line)
Code language: JavaScript ( javascript ) This is more than concise way to read a text file line by line.
Read UTF-eight text files
The code in the previous examples works fine with ASCII text files. All the same, if you lot're dealing with other languages such every bit Japanese, Chinese, and Korean, the text file is not a uncomplicated ASCII text file. And information technology'southward likely a UTF-8 file that uses more than than just the standard ASCII text characters.
To open a UTF-eight text file, yous need to laissez passer the encoding='utf-8' to the open() function to instruct it to expect UTF-viii characters from the file.
For the demonstration, you'll use the following quotes.txt file that contains some quotes in Japanese.
The post-obit shows how to loop through the quotes.txt file:
with open up('quotes.txt', encoding='utf8') as f: for line in f: print(line.strip())
Code language: JavaScript ( javascript ) Output:
Summary
- Employ the
open()function with the'r'mode to open a text file for reading. - Use the
read(),readline(), orreadlines()method to read a text file. - Always shut a file after completing reading it using the
close()method or thewithargument. - Employ the
encoding='utf-eight'to read the UTF-8 text file.
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Source: https://www.pythontutorial.net/python-basics/python-read-text-file/
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