[Python-Dev] Assignment expression and coding style: the while True case (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Thu Jul 5 07:06:12 EDT 2018

On Thu, 5 Jul 2018 13:58:42 +0300 Ivan Pozdeev via Python-Dev <python-dev at python.org> wrote:

On 05.07.2018 9:23, Serhiy Storchaka wrote: > 05.07.18 01:51, Victor Stinner пише: >> == Pattern 1, straighforward == >> >> while True: >>      line = input.readline() >>      if not line: >>          break >>      ... >> >> IMHO here assingment expression is appropriate here. The code remains >> straighfoward to read. >> >> while (line := input.readline()): >>      ... > > We already have an idiom for this: > > for line in input: >     ... >

This is not strictly equivalent: it has internal caching unaffected by -u and you can't iterate and .read() at the same time.

You are only talking about Python 2 here.

Regards

Antoine.

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