Python Cookbook, 3rd Edition

You need to read or write text data, possibly in different text encodings such as ASCII, UTF-8, or UTF-16.

Use the open() function with mode rt to read a text file. For example:

# Read the entire file as a single string with open('somefile.txt', 'rt') as f: data = f.read() # Iterate over the lines of the file with open('somefile.txt', 'rt') as f: for line in f: # process line ...

Similarly, to write a text file, use open() with mode wt to write a file, clearing and overwriting the previous contents (if any). For example:

# Write chunks of text data with open('somefile.txt', 'wt') as f: f.write(text1) f.write(text2) ... # Redirected print statement with open('somefile.txt', 'wt') as f: print(line1, file=f) print(line2, file=f) ...

To append to the end of an existing file, use open() with mode at.

By default, files are read/written using the system default text encoding, as can be found in sys.getdefaultencoding(). On most machines, this is set to utf-8. If you know that the text you are reading or writing is in a different encoding, supply the optional encoding parameter to open(). For example:

with open('somefile.txt', 'rt', encoding='latin-1')