How Often Does Python Flush Files and Standard Output?

Python File and Stdout Flushing

Question:

1. How frequently does Python flush data to a file?
2. Does stdout flushing occur after each newline in Python?

Answer:

1. File Operations: Python employs the operating system's default buffering policy for file operations. You can choose different buffering modes, including unbuffered, line buffered, and custom sizes. For instance, the open function allows you to specify a buffer size:

bufsize = 0
f = open('file.txt', 'w', buffering=bufsize)

Where 0 denotes unbuffered mode, 1 signifies line buffered mode, and any positive value indicates a buffer of the specified size. A negative value reverts to the system default, typically line buffered for terminals and fully buffered for other files.

2. Stdout Flushing: Python flushes data to stdout after every newline by default. However, if you redirect stdout to a file, the flushing behavior may vary. The system may apply different buffering policies to file output, potentially leading to different flushing intervals.

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