The for loop in Python is a control flow statement that is used to iterate over a sequence (such as a list, tuple, set, dictionary, or string) or other iterable objects. Here we present 12 multiple-choice questions to test your knowledge of Python For Loop. Each MCQ has the correct answer with an explanation.
1. What is the basic structure of a for loop in Python?
a) for item in iterable:
b) for (item in iterable)
c) for each item in iterable:
d) for item <= iterable:
Answer:
a) for item in iterable:
Explanation:
In Python, a for loop iterates over items of an iterable using the syntax 'for item in iterable:'.
2. How do you iterate over a range of numbers from 0 to 4 in Python?
a) for i in range(0, 5):
b) for i in range(5):
c) for i in range(1, 5):
d) Both a and b
Answer:
d) Both a and b
Explanation:
Both range(5) and range(0, 5) produce a sequence of numbers from 0 to 4.
3. How can you loop through a dictionary and access both keys and values?
a) for key in my_dict:
b) for key, value in my_dict.items():
c) for key in my_dict.keys() and value in my_dict.values():
d) for key, value in my_dict:
Answer:
b) for key, value in my_dict.items():
Explanation:
The items() method returns key-value pairs, which can be unpacked in a for loop.
4. What does the 'break' statement do inside a for loop?
a) Pauses the loop execution
b) Skips the current iteration
c) Exits the loop prematurely
d) Restarts the loop
Answer:
c) Exits the loop prematurely
Explanation:
The 'break' statement is used to exit the for loop before it has iterated over all items.
5. What is the role of the 'continue' statement in a for loop?
a) To stop the loop
b) To skip the current iteration and continue with the next
c) To pause loop execution
d) To terminate the loop immediately
Answer:
b) To skip the current iteration and continue with the next
Explanation:
The 'continue' statement skips the rest of the code inside a loop for the current iteration.
6. How do you iterate over both the elements of a list and their indices?
a) for i, item in enumerate(my_list):
b) for i in range(len(my_list)):
c) for item in my_list:
d) Both a and b
Answer:
d) Both a and b
Explanation:
You can use enumerate(my_list) or loop over the indices using range(len(my_list)).
7. What is the correct syntax for iterating over a list using a for loop?
a) for item in list:
b) for item <= list:
c) for item = list[0] to list[-1]:
d) for each item in list:
Answer:
a) for item in list:
Explanation:
The syntax for iterating over a list is 'for item in list:'.
8. How do you loop through the characters of a string 'hello'?
a) for char in 'hello':
b) for char in range(len('hello')):
c) for char in enumerate('hello'):
d) for char <= 'hello':
Answer:
a) for char in 'hello':
Explanation:
You can loop through a string directly by iterating over its characters.
9. What is the output of the following code?
for i in range(3):
print(i)
else:
print("Done")
a) 0 1 2 Done
b) 0 1 2
c) Done
d) 0 1
Answer:
a) 0 1 2 Done
Explanation:
The for loop iterates over 0, 1, 2, and then the else block is executed, printing "Done".
10. How can you loop through a tuple (1, 2, 3) and print each number?
a) for n in (1, 2, 3): print(n)
b) for n <= (1, 2, 3): print(n)
c) for n = 1 to 3: print(n)
d) for each n in (1, 2, 3): print(n)
Answer:
a) for n in (1, 2, 3): print(n)
Explanation:
You can iterate through a tuple by directly looping over its elements.
11. How do you create a nested for loop to iterate over a 2x2 matrix [[1,2],[3,4]]?
a) for i in matrix: for j in i: print(j)
b) for i in range(len(matrix)): for j in range(len(matrix[i])): print(matrix[i][j])
c) for [i, j] in matrix: print(i, j)
d) Both a and b
Answer:
d) Both a and b
Explanation:
Both methods correctly iterate over a nested list or matrix.
12. What is the purpose of the 'else' clause in a for loop?
a) To execute code when the loop condition is initially False
b) To execute code when the loop exits without encountering a break
c) To add an additional condition to the loop
d) To execute code at the end of each iteration
Answer:
b) To execute code when the loop exits without encountering a break
Explanation:
In Python, the else block in a for loop is executed when the loop completes normally without a break.
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