Stop a for Loop in Python

Stop a for Loop in Python

Najwa Riyaz Oct-02, 2021 Jul-01, 2021 Python Python Loop
  1. Use a break Statement to Stop a Python for Loop
  2. Wrap the Code in a Function, and Then Use the return Statement
  3. Raise an Exception to Stop a Python for Loop

This article introduces different methods to stop a for loop in Python.

Use a break Statement to Stop a Python for Loop

Use a break statement to stop a for loop in Python.

For example,

max=4
counter=0
for a in range(max):
   if counter==3:
         print("counter value=3. Stop the for loop")
         break
         
   else:
      print("counter value<3. Continue the for loop. Counter value=",counter)
      counter=counter+1
      continue
   break

Output:

counter value<3. Continue the for loop. Counter value= 0
counter value<3. Continue the for loop. Counter value= 1
counter value<3. Continue the for loop. Counter value= 2
counter value=3. Stop the for loop

Here, as long as the for loop criteria is met, the following print statement is printed. For example -

counter value<3. Continue the for loop. Counter value= 0

However, once the counter value is equal to 3, it breaks out of the for loop. Hence, the for loop stops.

Wrap the Code in a Function, and Then Use the return Statement

Wrap the code in a function, and then use the return statement.

For example,

def fncreturn():
   return;


max=4
counter=0
for a in range(max):
   if counter==3:
         print("counter value=3. Stop the for loop")
         fncreturn()         
   else:
      print("counter value<3. Continue the for loop. Counter value=",counter)
      counter=counter+1
      continue
   break

Output:

counter value<3. Continue the for loop. Counter value= 0
counter value<3. Continue the for loop. Counter value= 1
counter value<3. Continue the for loop. Counter value= 2
counter value=3. Stop the for loop

Here, when the counter value reaches to 3, the function is called. The function has just a return statement. Post that, it helps exit from the for loop.

Raise an Exception to Stop a Python for Loop

Raise an exception to stop a for loop.

For example,

max=4
counter=0
try:
    for a in range(max):
       if counter==3:
         print("counter value=3. Stop the for loop")
         raise StopIteration   
       else:
          print("counter value<3. Continue the for loop. Counter value=",counter)
          counter=counter+1
      
except StopIteration:
   pass

Output:

counter value<3. Continue the for loop. Counter value= 0
counter value<3. Continue the for loop. Counter value= 1
counter value<3. Continue the for loop. Counter value= 2
counter value=3. Stop the for loop

Here, when the counter value reaches to 3, the exception is raised. Immediately it exits from the for loop.

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