Python string MCQ questions with answers

Answer: B

Indexes start at 0, so s[0] is P and s[2] is T. Negative indexes count from the end, and s[-1] is the last character, N.

Answer: C

A slice s[start:stop] includes the start index and stops before the stop index, so s[3:7] takes indexes 3, 4, 5 and 6: g, r, a, m.

Answer: A

s[-3:] starts three characters from the end and runs to the end, giving ter. s[:-3] runs from the start up to, but not including, that same position, giving compu.

Answer: D

The third number in a slice is the step. s[::2] takes every second character from index 0 (aceg), and s[1::3] takes indexes 1, 4 and 7 (beh).

Answer: C

With a step of -1 the slice walks backwards from s[-2] (O) and stops before s[-5] (Y), so it takes O, H, T. The stop index is never included, and s[-1] is not the start here.

Answer: D

Strings are immutable, so upper() returns a new string instead of changing name. The result is thrown away because it is not assigned; name = name.upper() would keep it.

Answer: B

With no argument, split() splits on any run of whitespace, so the double space acts as one separator. split(" ") splits at every single space, so the two spaces leave an empty string between them.

Answer: A

"-".join(letters) puts the separator only between the items, not at the ends. "".join(letters) gives abc, and upper() turns it into ABC.

Answer: D

find() returns the index of the first match, and an first appears at index 1. count() counts non-overlapping matches (2). When there is no match, find() returns -1 rather than raising an error.

Answer: C

The third argument of replace() limits how many replacements are made, starting from the left, so only the first two - change. replace() returns a new string, so s itself is unchanged.

Answer: A

Strings compare character by character using Unicode code points. Uppercase letters come before lowercase ones (B is 66, a is 97), so "apple" < "Banana" is False. "10" < "9" compares 1 with 9 first, so it is True.

Answer: D

strip() removes the outer spaces and upper() gives AB-2024. It starts with AB and contains 2024, but isdigit() is False because the string also has letters and a hyphen.

Answer: B, TypeError: 'str' object does not support item assignment

Strings are immutable, so you cannot assign to one of their characters. Build a new string instead, for example word = "b" + word[1:].

Answer: A, TypeError: sequence item 0: expected str instance, int found

join() accepts only strings, and it does not convert numbers for you. Convert the items first: "-".join(str(n) for n in [1, 2, 3]) gives 1-2-3.

Answer: C, IndexError: string index out of range

A slice never raises an error: s[2:10] stops at the end of the string and prints thon. A single index must exist, so s[10] raises IndexError.

Answer: C, 3

The escape sequence \n is written with two symbols but stands for one character, a newline. So the string holds a, a newline and b: three characters.

Answer: A, find() returns -1 and index() raises ValueError

Both methods return the position of the first match. When there is no match, find() returns -1, while index() raises ValueError: substring not found.

Answer: D, len(s) - 1

Indexes run from 0 to len(s) - 1, and -1 is a shortcut for that last position. s[len(s)] raises IndexError, and -0 is the same as 0, the first character.

Answer: B

A slice with step -1 walks the whole string backwards and returns a new string. Strings have no reverse() method, reversed(s) returns an iterator rather than a string, and s[-1:0:-1] stops before index 0, losing the first character.

Answer: B

In 8.2f, 8 is the minimum width and .2f gives two decimals; numbers are right-aligned by default, so 42.50 gets three spaces in front. < would left-align it, .8f shows eight decimals, and 8 alone keeps 42.5.