Original Translation
41
Many alternatives have been proposed. Most are hacks that save some typing but use arbitrary or cryptic syntax or keywords, and fail the simple criterion for language change proposals: it should intuitively suggest the proper meaning to a human reader who has not yet been introduced to the construct.
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An interesting phenomenon is that most experienced Python programmers recognize the ``while True`` idiom and don't seem to be missing the assignment in expression construct much; it's only newcomers who express a strong desire to add this to the language.
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There's an alternative way of spelling this that seems attractive but is generally less robust than the "while True" solution::
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line = f.readline() while line: ... # do something with line... line = f.readline()
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The problem with this is that if you change your mind about exactly how you get the next line (e.g. you want to change it into ``sys.stdin.readline()``) you have to remember to change two places in your program -- the second occurrence is hidden at the bottom of the loop.
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The best approach is to use iterators, making it possible to loop through objects using the ``for`` statement. For example, in the current version of Python file objects support the iterator protocol, so you can now write simply::
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for line in f: ... # do something with line...
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Why does Python use methods for some functionality (e.g. list.index()) but functions for other (e.g. len(list))?
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The major reason is history. Functions were used for those operations that were generic for a group of types and which were intended to work even for objects that didn't have methods at all (e.g. tuples). It is also convenient to have a function that can readily be applied to an amorphous collection of objects when you use the functional features of Python (``map()``, ``apply()`` et al).
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In fact, implementing ``len()``, ``max()``, ``min()`` as a built-in function is actually less code than implementing them as methods for each type. One can quibble about individual cases but it's a part of Python, and it's too late to make such fundamental changes now. The functions have to remain to avoid massive code breakage.