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How to get all concatenation of list elements in order in Python?

background

I have lists of numbers and symbols like:

[1,':',2022,'.','01','.','01']

I would like to call a function like is_date(string) on every concatenation of the elements in order.

minimal example

Considering the simple example [1,2,3] as input, the expected list of concatenations should be: ['1','12','2','123','23','3']

I would like not to get '13' in the results

So afterwards I could call:

for token in list_of_concatenation:
    if is_date(token):
        do something
Solution

  • You can use a double loop, slicing, and string concatenation:

    l = [1, 2, 3]
l2 = [str(x) for x in l]
[''.join(l2[i:j+1]) for i in range(len(l2)) for j in range(i, len(l2))]

    output: ['1', '12', '123', '2', '23', '3']