Python中的Dict理解而不是PEP8

Question

My Sublime Linter for Python 2.7 reports that this line is not PEP8:

D = {k:get_distance(v) for k, v in D.items() if len(v) > 1}

in column 8 and 27

but when I insert a space after colon ( : ), I get a red exclamation mark in Sublime.

How to make this line PEP8 compliant?

Update

Sublime Text 2.0.2, build 2221 ; Sublime Linter v1.8 ; Python PEP8 Lint v2013.10.11.06

Code works and produces output without error

Answer 1

Insert a space after the : ; this is still valid Python syntax:

D = {k: get_distance(v) for k, v in D.items() if len(v) > 1}

If you are getting a syntax error, you introduced that somewhere else. Perhaps you forgot to close a ) parenthesis on the preceding line, for example.

Note that using a capital letter as a local variable is not PEP-8 compliant. Pick better, lowercase_with_underscores names for local variables:

def solution(seq):
    positions = defaultdict(list)
    for i, item in enumerate(seq):
        positions[item].append(i)
    distances = {k: get_distance(v) for k, v in positions.items() if len(v) > 1}
    return max(distances.value()) if distances else 0

Last but not least; your indices in the positions dictionary are ordered (incrementing), so get_distance() should just return l[-1] - l[0] to make it return a distance in O(1) constant time.

Answer 2

D = {k: get_distance(v) for k, v in D.items() if len(v) > 1}

This is not a syntactical error and is the correct PEP8 way to write it. Check that you do not have any hidden unicode character in there.