Returning a value based on index number of each element in a list

Question

I am trying to identify the first element, last element, and other elements in a python list using a function. If it’s the first element, I want 0 to be returned, if it’s the last element I want -1 to be returned, every other element should return 2.

I can achieve this without using a function but when I use a function, I don’t get the desired result. Please help me with this. Thanks in advance

What I have so far can be seen in the codes and screenshots below here is the code without using a function

a= [1,2,3,4,5,6]
    for i, x in enumerate(a):
        if i==0:
            number=0 
        elif i==len(a)-1:
            number=-1
        else:
            number=2 
        print (number)

here is the desired output, it is gotten when function is not used

here is the same code in a function

def cs():
    a= [1,2,3,4,5,6]
    for i, x in enumerate(a):
        if i==0:
            number=0 
        elif i==len(a)-1:
            number=-1
        else:
            number=2 
        print (number)
        return (number)
cs()

here is the output of the function. it returns only one index instead of six

If i try having the print/return statement outside the for loop, only the last element returns a value.

def cs():
    a= [1,2,3,4,5,6]
    for i, x in enumerate(a):
        if i==0:
            number=0 
        elif i==len(a)-1:
            number=-1
        else:
            number=2 
    print (number)
    return (number)
cs()

here is the output of the function with the print/return statement outside the for loop

Never post code as images, simply copy/paste the code directly to your question and format it as code. — Cow, Dec 22 '22 at 07:22
you have a `return` statement in your function. this exits the function, after the first iteration of the loop — Jeanot Zubler, Dec 22 '22 at 07:25
Does this answer your question? [Finding the index of an item in a list](https://stackoverflow.com/questions/176918/finding-the-index-of-an-item-in-a-list) — RandomGuy, Dec 22 '22 at 07:25
@JeanotZubler thanks for your response! is it possible to iterate through the whole list and still use a return statement? — Cassie, Dec 22 '22 at 07:58
@RandomGuy not really. I need the code to return a particular value for the first element, another value the last element, and then the same value for the “middle” elements. — Cassie, Dec 22 '22 at 08:09

score 0 · Accepted Answer · answered Dec 22 '22 at 08:15

Your query- is it possible to iterate through the whole list and still use a return statement?

Instead of return we use yield to go through whole list.

def generator():
    a= [1,2,3,4,5,6]
    for i,x in enumerate(a):
        if i==0:
            yield 0 
        elif i==len(a)-1:
            yield -1
        else:
            yield 2

gen_object = generator()
print(type(gen_object))
for i in gen_object:
   print(i)

Output:-

<class 'generator'>
0
2
2
2
2
-1

Returning a value based on index number of each element in a list

1 Answers1