Python While Loops

Python Loops

Python has two primitive loop commands:

• while loops
• for loops

---

The while Loop

With the while loop we can execute a set of statements as long as a condition is true.

Example

Print i as long as i is less than 6:

i = 1
while i < 6:
  print(i)
  i += 1

Show Python »
C:\Users\My Name>python demo_while.py
1                                    
2                                    
3                                    
4                                    
5                                    
                                     
                                     

Note: remember to increment i, or else the loop will continue forever.

The while loop requires relevant variables to be ready, in this example we need to define an indexing variable, i, which we set to 1.

---

The break Statement

With the break statement we can stop the loop even if the while condition is true:

Example

Exit the loop when i is 3:

i = 1
while i < 6:
  print(i)
  if i == 3:
    break
  i += 1

Show Python »
C:\Users\My Name>python demo_while_break.py
1                                          
2                                          
3                                          
                                           
                                           

---

---

The continue Statement

With the continue statement we can stop the current iteration, and continue with the next:

Example

Continue to the next iteration if i is 3:

i = 0
while i < 6:
  i += 1 
  if i == 3:
    continue
  print(i)

Show Python »
C:\Users\My Name>python demo_while_continue.py
1                                             
2                                             
4                                             
5                                             
6