For Loops in Python Programming

for Loop:

• use to iterate over a sequence (like a list, tuple, string, or range) and execute a block of code multiple times, once for each item in the sequence.

Basic Syntax:

for variable in sequence:
    # Code to execute for each item in the sequence

Example:

Iterating Over a List:

• In the below example, the loop iterates over each item in the SAARC_Country list, and the country takes on the value of each item in the list during each iteration.

SAARC_Country = ["Bangladesh", "India", "Pakistan","Nepal","Bhutan","Afghanistan","Maldives","Sri-Lanka"]

for country in SAARC_Country:
    print(country)

Output:
Bangladesh
India
Pakistan
Nepal
Bhutan
Afghanistan
Maldives
Sri-Lanka

Using range():

• The range() function generates a sequence of numbers, often used with loops to repeat a block of code a specific number of times.
• In the example below, range(10) generates the numbers 0 to 9, and the loop prints each number.

for i in range(10):
    print(i)

Output:
0
1
2
3
4
5
6
7
8
9

Iterating Over a String:

• We can use a for loop to iterate over the characters in a string

for name in "Masud Rana":
    print(name)

Output:
M
a
s
u
d
 
R
a
n
a

Nested for Loops:

• We can nest for loops to iterate over multi-dimensional sequences (like lists of lists).

matrix = [[1, 2, 3], 
          [4, 5, 6], 
          [7, 8, 9]]

for row in matrix:
    for item in row:
        print(item)

Output:
1
2
3
4
5
6
7
8
9

matrix = [[1, 2, 3], 
          [4, 5, 6], 
          [7, 8, 9]]

for row in matrix:
    for item in row:
        print(item, end=" ") #end=" " is used to keep the output of each row on the same line with a space 
                                          separating each item.
    print() 

Output:
1 2 3 
4 5 6 
7 8 9 

The break Statement:

• If we want to stop the loop before it loop through all items, we can use ‘break” statement

SAARC_Country = ["Bangladesh", "India", "Pakistan","Nepal","Bhutan","Afghanistan","Maldives","Sri-Lanka"]

for country in SAARC_Country:
    print(country)
    if country== 'Bhutan':
      break

Output:
Bangladesh
India
Pakistan
Nepal
Bhutan

The continue Statement:

• With the continue statement, we can stop the current iteration of the loop, and continue with the next item

SAARC_Country = ["Bangladesh", "India", "Pakistan","Nepal","Bhutan","Afghanistan","Maldives","Sri-Lanka"]

for country in SAARC_Country:
    if country== 'Bhutan':
      continue
    print(country)

Output:
Bangladesh
India
Pakistan
Nepal
Afghanistan
Maldives
Sri-Lanka