CODEWITHSUNDEEP
pythonlist
dana111
dana111

Reputation: 469

How to check that each list in a list of list is the same length

I have a list and a list of list

A=["grp 1", "grp 2"]
B=[["1","2"],["3","4"],["5","6"]]

how do I check that each list in B is equal to the length of A?

I would like something like 

if len(A) != len(list in B):
     raise ValueError('special error message')

Upvotes: 3

Views: 53

Answers (2)

Copperfield
Copperfield

Reputation: 8520

as additional note, if you want to know if every element in the list have the same length regardless of its value, you can use

len( set( len(x) for x in my_list ) ) == 1

with set you eliminate all duplicates so if in the end if its length is more than one then some stuff there have different size

Upvotes: 0

MrAlexBailey
MrAlexBailey

Reputation: 5289

If you want to make sure that every single element of B is not equal to the length of A then you can use:

a_len = len(A)
all(len(x) != a_len for x in B)

Alternatively you can use the following if you want to see if any element of B is not the same length as A:

a_len = len(A)
any(len(x) != a_len for x in B)

So in your case you could use:

a_len = len(A)
if any(len(x) != a_len for x in B):
    raise error

Upvotes: 3

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