While Loops
Condition-based iteration
Interview Relevant: Loop control
While Loops
Loop while a condition is true.
Code Examples
While loop patterns.
python
1# Basic while
2count = 0
3while count < 5:
4 print(count)
5 count += 1
6
7# Infinite loop with break
8while True:
9 user_input = input("Enter 'quit' to exit: ")
10 if user_input == 'quit':
11 break
12
13# while with else (rarely used)
14n = 5
15while n > 0:
16 print(n)
17 n -= 1
18else:
19 print("Loop completed normally")
20
21# Reading until EOF
22import sys
23while line := sys.stdin.readline():
24 print(line)