How do I find out if a value is in a deque?

Question

say i have a deque with values [0,3,5,1,5,8]. I want to save all information about the deque including order, but I have to find if the value 5 is in the deque.

What is some pseudo-code that could determine this?

score 10 · Accepted Answer · answered Feb 04 '15 at 01:36

10

Are you aware of the in operator?

>>> import collections
>>> d = collections.deque([0,3,5,1,5,8])
>>> 5 in d
True
>>> 20 in d
False

answered Feb 04 '15 at 01:36

Bill Lynch

80,138
16
128
173

what would be a good implementation of `list.index()` like function for `collections.deque`? Thanks – Abdullah Giray Yağlıkçı Jan 08 '18 at 08:47
4

What about the time complexity of the operation – LeonF Jun 05 '19 at 20:21

score 3 · Answer 2 · answered Feb 04 '15 at 01:58

Although most of the time you'd want to use the in operator for membership testing, which deques support, you also have the option of using its count() method — which actually provides more information and so might be more useful depending on exactly what you're trying to accomplish.

>>> import collections
>>> d = collections.deque([0, 3, 5, 1, 5, 8])
>>> d.count(5)
2
>>> d.count(20)
0
>>> bool(d.count(5))
True
>>> bool(d.count(20))
False

How do I find out if a value is in a deque?

2 Answers2