String Slicing in List Comphrensions

String Slicing in List Comphrensions - Printable Version

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String Slicing in List Comphrensions - Patroclus72790 - Mar-21-2019

Hello!

I have a question about the following code:
Example 1

str = "hello"
i = str[2]
str[i]
TypeError: string indices must be integers

So the result is as expected: When you attempt to slice a string with a string, you get a type error.

However, when I do the same thing inside a list comprehension as below, we get a different result.

Example 2

result = [str[:i] + str[i].upper() + str[i+1:] for i in range(len(str))]
['Hello', 'hEllo', 'heLlo', 'helLo', 'hellO']

Why does this happen? My guess is that slicing might function differently when used in a list comprehension, but this has been giving me a headache for some time this afternoon.

Thanks for the assistance!
Vale

RE: String Slicing in List Comphrensions - nilamo - Mar-21-2019

That isn't the same thing. In the second example, i is always an int.