I was trying to do an assignment operation in python single line for loop like
[a[i]=b[i] for i in range(0,len(b))]
This seems wrong. Is there a way I can use assignment operation in python single line for loop?
5 Answers
You are mixing two paradigms here, that of loop and list comprehension. The list comprehension will be
a = [x for x in b]
2 Comments
jeffery_the_wind
or why not
a = b[:]
Elan
Does the same, but I think OP is trying to learn list comprehension as an alternative to looping over list. This explicitly conveys the idea.
No need for a loop. You can use a slice assignment:
a[0:len(b)]= b
Comments
Copy lists can be done in many ways in Python.
Using slicing
a = b[:]
Using
list()a = list(b)
1 Comment
You could use:
[a.__setitem__(i, b[i]) for i in range(0,len(b))]
the __setitem__ is the method that implements index-assignment. However doing a list comprehension only because of side-effects is a big no-no.
You could simply use slice-assignment:
a[:len(b)] = b
Comments
in python 3 it can be done by:
a = b.copy()
aandbhave the same length? And what is your use-case? Maybe there's an even better way (without loops or comprehensions).