how to insert the elements in a list properly?

Peter Otten __peter__ at web.de
Wed Apr 9 06:46:24 EDT 2014


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']





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