Python 3: An interactive deep dive/

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Indenting Code

Indenting Code

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Python functions have no explicit begin or end, and no curly braces to mark where the function code starts and stops. The only delimiter is a colon (:) and the indentation of the code itself.

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def approximate_size(size, a_kilobyte_is_1024_bytes=True):  #①
    if size < 0:                                            #②
        raise ValueError('number must be non-negative')     #③
                                                            #④
    multiple = 1024 if a_kilobyte_is_1024_bytes else 1000
    for suffix in SUFFIXES[multiple]:                       #⑤
        size /= multiple
        if size < multiple:
            return '{0:.1f} {1}'.format(size, suffix)
    raise ValueError('number too large')

① Code blocks are defined by their indentation. By “code block,” I mean functions, if statements, for loops, while loops, and so forth. Indenting starts a block and unindenting ends it. There are no ...