Why Does \"ar[i]\" Throw an IndexError in a \"for i in ar\" Loop?

Identifying the Issue: Why an IndexError Occurs in "ar[i]" within "for i in ar"

In Python, when coding a for loop to sum values in a list, an IndexError may arise if you attempt to access elements using "ar[i]" where "i" represents the current element of the list.

Understanding the Error

The error occurs because "ar[i]" attempts to index into the list using the current element as the index. However, the current element is not the index itself but the value at that index. In the given code, you are attempting to use a value as an index, which is not permitted.

Resolving the Issue

To resolve this error, modify the loop as follows:

for i in ar:
    theSum = theSum + i

Instead of indexing the list with "i", you directly add the current element represented by "i" to "theSum".

Alternative Solution: Using Range

Alternatively, you can employ a range loop:

for i in range(len(ar)):
    theSum = theSum + ar[i]

"range(len(ar))" generates a range of valid indices for the list, and you can use "ar[i]" within this loop without encountering the error.

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