2.8. builtin - File Input/Output (IO)¶

2.8.1. Syntax¶

Although there are many ways to work with files, by far the safest is with “Context Manager”, see builtin - Context Manager. A Context Manager has an Enter and an Exit protocol that handles events. In terms of file IO, with open opens a file stream on Enter, and closes file stream on Exit, therefore files are always closed down once the code is done streaming it.

# read a file
with open("filename.txt", "r") as f:
    while True:
        line = f.readline()
        if not line:
            break

# write a file
text = ["hello", "world"]
with open("filename.txt", "w") as f:
    for line in text:
        f.write(line + "\n")

Open file object modes:

r: read only
w: write only
x: execution only
a: append to existing file
b: binary mode (this is combined with r or w
+: open for updating (reading/writing)

2.8. builtin - File Input/Output (IO)¶

2.8.1. Syntax¶

2.8.2. Working with directories¶