CODEWITHSUNDEEP
pythonlistpython-2.7
ElefEnt
ElefEnt

Reputation: 2127

Startswith for lists in python?

Is there an equivalent of starts with for lists in python ?

I would like to know if a list a starts with a list b. like

len(a) >= len(b) and a[:len(b)] == b ?

Upvotes: 3

Views: 1372

Answers (3)

sloth
sloth

Reputation: 101072

For large lists, this will be more efficient:

from itertools import izip
...
result = all(x==y for (x, y) in izip(a, b))

For small lists, your code is fine. The length check can be omitted, as DavidK said, but it would not make a big difference.

PS: No, there's no build-in to check if a list starts with another list, but as you already know, it's trivial to write such a function yourself.

Upvotes: 0

MultiVAC
MultiVAC

Reputation: 354

it does not get much simpler than what you have (and the check on the lengths is not even needed)... for an overview of more extended/elegant options for finding sublists in lists, you can check out the main answer to this post : elegant find sub-list in list

Upvotes: -1

DavidK
DavidK

Reputation: 2564

You can just write a[:len(b)] == b

if len(b) > len(a), no error will be raised.

Upvotes: 6

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