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Get the previous value based on a specific element

I am trying to use a script where we use a list item and then get the previous item.

lst = [1, 3, 4, 6, 8, 10]

next_item = next((x for x in lst if x > 6), None)
print next_item #8

This code works correctly for the element after 6. However, I need the element before 6.

I look in the docs for the prev method but I can't find anything related. Any ideas about this?

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3 answers


Assuming "before" you mean "previous in lst

", there is no need to use such a complicated method. it

lst[lst.index(6) - 1]

will give

4

while this



lst[lst.index(6) + 1]

will give

8

Of course, you should check for any index related errors.

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You can flip a reversible list with the opposite condition:



>>> next((i for i in lst[::-1] if i<6),None)
4
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If you're looking for the first number greater than 6 in lst

, this is one way to do it:

lst = [1, 3, 4, 6, 8, 10]
lst2 =[]
for num in lst:
    if num > 6:
        lst2.append(num)
        lst2.sort()
print lst2[0]

Output signal 8

0


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