How to find out if certain values are contained in a list, order matters

Question

a = [1,1,0,0,0,'yes',1,1,0]

b = [1,1,0,0,0,'yes',0,1,1]

pattern = ['yes',1,1] #The main lists a and b should check for the pattern in the same order

I'm expecting an output like:

pattern in a - should give 'Yes' or True

pattern in b - should give 'No' or False

Merging the values in the list to form 1 string and checking with an if - in condition is not the path I'm looking for.

This isn't a code-writing service; what have you tried, and what exactly is the problem with it? — jonrsharpe, Jul 19 '18 at 17:11
relevant: https://stackoverflow.com/questions/10106901/elegant-find-sub-list-in-list — Green Cloak Guy, Jul 19 '18 at 17:11
I've tried to loop through both like one loop within the other, but it loses sense of the pattern and starts checking for individual elements. — nisha21_m, Jul 19 '18 at 17:17
How is this different than: https://stackoverflow.com/questions/10106901/elegant-find-sub-list-in-list ? — Mircea, Jul 19 '18 at 17:21

score 2 · Accepted Answer · answered Jul 19 '18 at 17:20

2

You can use any with a generator comprehension and list slicing:

a = [1,1,0,0,0,'yes',1,1,0]
b = [1,1,0,0,0,'yes',0,1,1]
pattern = ['yes',1,1]

def comparer(L, p):
    n = len(p)
    return any(L[i:i+n] == p for i in range(len(L)-n))

comparer(a, pattern)  # True
comparer(b, pattern)  # False

answered Jul 19 '18 at 17:20

jpp

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Oh! This works perfectly. Thank you for your help. I really appreciate it!! – nisha21_m Jul 19 '18 at 17:22
1

@nisha21_m also, unlike the other answer, this will maintain `type` integrity as well. – user3483203 Jul 19 '18 at 17:23

Sunitha · Answer 2 · 2018-07-19T17:40:32.073

0

>>> a = [1,1,0,0,0,'yes',1,1,0]
>>> b = [1,1,0,0,0,'yes',0,1,1]
>>> pattern = ['yes',1,1]
>>> 
>>> tuple(pattern) in zip(*[a[i:] for i in range(len(pattern))])
True
>>> 
>>> tuple(pattern) in zip(*[b[i:] for i in range(len(pattern))])
False
>>>

edited Jul 19 '18 at 17:40

answered Jul 19 '18 at 17:34

Sunitha

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No need for the intermediary list creation: `tuple(pattern) in zip(*(a[i:] for i in range(len(pattern))))`. – jpp Jul 19 '18 at 18:17

How to find out if certain values are contained in a list, order matters

2 Answers2