PythonBuilt-in functions
open()
Opens a file for reading or writing and returns a file object.
- Returns
- A file object.
Example
#Python
with open("progress.txt", "w", encoding="utf-8") as file:
file.write("HTML: done\n")
file.write("CSS: in progress\n")
with open("progress.txt", encoding="utf-8") as file:
for line in file:
print(line.strip())Resultsaved result, you can check it
HTML: done
CSS: in progress
Definition and usage
#The open(path, mode) function opens a file. The mode "r" (the default) is for reading, "w" for writing with overwrite, "a" for appending at the end, and "x" creates a new file and raises an error if it already exists. The letter b in the mode means a binary file.
Always open a file inside a with block. It then gets closed automatically when the block ends, even if an error occurs.
For text files, pass encoding="utf-8". The default encoding depends on the system, so without it, accented characters can look different on different computers.
Syntax
#Syntax
open(file, mode="r", encoding=None)Parameters
#file
str or path
The path to the file.mode
str, default "r"
The mode:r,w,a,x, with an optionalbor+.encoding
str, optional
The text encoding, usually"utf-8".
Good practices
#- The
"w"mode erases the contents already in the file. To append instead, use"a". - For working with paths, the
pathlibmodule is more convenient:Path("file.txt").read_text(encoding="utf-8").
Related entries
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