words = ["x1", "x2", "x3", "x4", "x5"] words.append(words.pop(2)) words.append(words.pop(2)) words ['x1', 'x2', 'x5', 'x3', 'x4'] why i can't write it as:
[words.append(words.pop(2)) for i in range(0,2)] >>> [words.append(words.pop(2)) for i in range(0,2)] [None, None] 2014-04-09 18:46 GMT+08:00 Peter Otten <__pete...@web.de>: > length power wrote: > > > word=["x1","x2","x3","x4","x5"] > > w=word[-2:] > > del word[-2:] > > word.insert(2,w) > > word > > ['x1', 'x2', ['x4', 'x5'], 'x3'] > > > > what i want to get is > > ['x1', 'x2', 'x4', 'x5', 'x3'] > > > > how can i insert them ? > > Make the left-hand side an empty slice: > > >>> words = ["x1", "x2", "x3", "x4", "x5"] > >>> w = words[-2:] > >>> del words[-2:] > >>> words[2:2] = w > >>> words > ['x1', 'x2', 'x4', 'x5', 'x3'] > > Or note that the operation is equivalent to moving the third item to the > end: > > >>> words = ["x1", "x2", "x3", "x4", "x5"] > >>> words.append(words.pop(2)) > >>> words > ['x1', 'x2', 'x4', 'x5', 'x3'] > > > -- > https://mail.python.org/mailman/listinfo/python-list >
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