How to conditionally delete elements from list-of-tuples?

Question

>>> x=[("x1","x2","x3"),("x1","x2"),("x2","x3"),("x3","x4")]
>>> x
[('x1', 'x2', 'x3'), ('x1', 'x2'), ('x2', 'x3'), ('x3', 'x4')]

I want to delete the tuple in the list--x ,if len(x[id])==3 ,len(x[0]==3) ,so it will be deleted ,[('x1', 'x2'), ('x2', 'x3'), ('x3', 'x4')] is what i wanted,how can i write the code?

[del element if len(element[id]==3) for id,element in enumerate(x)]

invalid syntax.

Martijn Pieters · Accepted Answer · 2014-03-27T13:19:56.507

6

Use a list comprehension to filter elements, keeping everything not length 3:

x = [el for el in x if len(el) != 3]

Demo:

>>> x = [('x1', 'x2', 'x3'), ('x1', 'x2'), ('x2', 'x3'), ('x3', 'x4')]
>>> [el for el in x if len(el) != 3]
[('x1', 'x2'), ('x2', 'x3'), ('x3', 'x4')]

edited Mar 27 '14 at 13:19

answered Mar 27 '14 at 13:12

Martijn Pieters

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Or as a slightly less pythonic way: `x = filter(lambda el: len(el) != 3, x)`. – Phylogenesis Mar 27 '14 at 13:16
which, in Python 3, produces an iterator and not a list. – Martijn Pieters Mar 27 '14 at 13:19

How to conditionally delete elements from list-of-tuples?

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