Python

1: Print Function
2: Escape Sequence
3: Comments
4: Escape Sequence as Normal Text
5: Print Emoji
6: Python as Calculator
7: Strings Concatenation
8: Input
9: int function
10: Variables
11: String Formatting
12: String Indexing
13: String Slicing
14: Step Argument
15: Some useful function and methods
16: Strip Method
17: Find and Replace method
18: Center method
19: If Statement
20: If else statement
21: Nested if-else Statement
22: if-elif-else statement
23: while loop
23.1: Example 1 while loop
23.2: Example 2 while loop
23.3: Example 3 while loop
24: Infinite loop
25: for loop
25.1: Example 1 for loop
26: break and continue statement
27: for loop with string

Chapter 23.1: Example 1 while loop

#sum of n natural number
num = int(input("how many natural numbers sum you want: "))
total = 0
i     = 0
while i < num:
  total += i+1
  i     += 1
print(f"Total sum of {num} natural numbers is {total}")
Output:
how many natural numbers sum you want: 10
Total sum of 10 natural numbers is 55