How to get list index and element simultaneously in Python?
42842 Репутация автора
I find myself frequently writing code like this:
k = 0 for i in mylist: # y[k] = some function of i k += 1
Instead, I could do
for k in range(K): # y[k] = some function of mylist[k]
but that doesn't seem "pythonic". (You know... indexing. Ick!) Is there some syntax that allows me to extract both the index (k) and the element (i) simultaneously using either a loop, list comprehension, or generator? The task is in scientific computing, so there is a lot of stuff in the loop body, making a list comprehension probably not powerful enough on its own, I think.
I welcome tips on related concepts, too, that I might not have even though of. Thank you.Автор: Steve Tjoa Источник Размещён: 15.01.2010 02:56
599640 Репутация автора
You can use
for k,i in enumerate(mylist): #do something with index k #do something with element i
More information about looping techniques.
As pointed out in the comments, using other variable names like
for i, item in enumerate(mylist):
makes it easier to read and understand your code in the long run. Normally you should use
k for numbers and meaningful variable names to describe elements of a list.
I.e. if you have e.g. a list of books and iterate over it, then you should name the variable