CODEWITHSUNDEEP
pythonvariablesincrement
heihei
heihei

Reputation: 101

How to increment variables inside argument?

In the code below I want to creat a string list and I pass a variable min to a method as an argument:

max_list = [1 , 2 , 3]
min = 0
output = ["{a} + {b}".format(a=min, b=max) for max in max_list]

However, I want to increment min every time I generate a list object. Is there a python way to achieve the same result of ++ operator? Apparently, I can't use min++ in this case as it is python code.

Expected Result:

['0 + 1', '1 + 2', '2 + 3']

Upvotes: 0

Views: 361

Answers (3)

alex_noname
alex_noname

Reputation: 32073

Since Python 3.8 you can use assignment expression :=. But since the increment will occur before the return of the expression result like ++min, you need to initialize min to -1

max_list = [1 , 2 , 3]
min = -1
output = ["{a} + {b}".format(a=(min := min + 1) , b=max) for max in max_list]

Upvotes: 0

Roy Cohen
Roy Cohen

Reputation: 1570

You didn't share your expected output so this may not be what you wanted, but...

max_list = [1, 2, 3]
output = [f"{min} + {max}" for min, max in enumerate(max_list)]
print(output)

Output:
['0 + 1', '1 + 2', '2 + 3']

Upvotes: 3

Daweo
Daweo

Reputation: 36360

Firstly min and max are unfortunate variable names in python, as they shadow built-in min and max functions. As for increasing by 1 you might harness itertools.count following way:

import itertools
max_list = [1 , 2 , 3]
mn = itertools.count(0)
output = ["{a} + {b}".format(a=next(mn), b=mx) for mx in max_list]
print(output)

Output:

['0 + 1', '1 + 2', '2 + 3']

Upvotes: 1

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