تمارين فهرسة القوائم والأطوال

You will need to look at all the possible indices of things and check which one is the answer.

To look at all possible indices, you will need a loop over range(len(things)).

To check if an index is the answer, you will need to use:

• if

• the index in a subscript

• ==

Since you're looking for the first index, you need to stop the loop once you find one.

You learned how to stop a loop in the middle recently.

You need to use break.

Did you experiment with indexing and len() with strings in the shell?

Forget loops for a moment. How would you print just the first line, which has the first character of each of the two strings?

In the second line you want to print the second character of each string, and so on.

You will need a for loop.

You will need indexing (subscripting).

You will need range.

You will need len.

You will need +.

You will need to index both strings.

You will need to pass the same index to both strings each time to retrieve matching characters.

The solution has the same overall structure and essential elements of the previous solution, but it's significantly longer and will require a few additional ideas and pieces.

What should go inside range()? Neither len(string1) nor len(string2) is good enough.

You want a loop iteration for every character in the longer string.

That means you need range(<length of the longest string>)

In other words you need to find the biggest of the two values len(string1) and len(string2). You've already done an exercise like that.

Once you've sorted out for i in range(...), i will sometimes be too big to be a valid index for both strings. You will need to check if it's too big before indexing.

Remember, the biggest valid index for string1 is len(string1) - 1. len(string1) is too big.

You will need two if statements, one for each string.

You will need to set e.g. char1 = ' ' when string1[i] is not valid.