 # Double Index Code Challenge question

Regarding this exercise:

Create a function named `double_index` that has two parameters named `lst` and `index` .

The function should double the value of the element at `index` of `lst` and return the new list with the doubled value.

If `index` is not a valid index, the function should return the original list.

def double_index(lst, index):
if index < len(lst):

``````   I DON'T UNDERSTAND THIS LINE IN THE SOLUTION:
lst[index] = lst[index] * 2
``````

return lst

#Uncomment the line below when your function is done
print(double_index([3, 8, -10, 12], 3))

HOW CAN SOMETHING BE SET TO EQUAL ITSELF TIMES 2? SEEMS LIKE THERE SHOULD BE A CLEARER WAY TO REPRESENT THIS? THANKS.

it can’t, but in programming a single equal sign (`=`) means assign. It doesn’t mean set equal to. So we get the value from `lst` at `index`, multiple it by 2, and store it in the list again.

Thanks for the reply. That helps.

You can also use this operator:

``````    lst[index] *= 2
``````

I believe it accomplishes the same thing as: lst[index] = lst[index] * 2

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