How to use while & for loops

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COMP 1010 Home > Back to Extra Labs

Introduction

In this program, you will be learn how to use while and for loop control structures in Python.

  • while and for loops syntax in Python: while (expression): Statement(s) for iterating_var in sequence: Statements(s) The program below shows how to print out alphabets in a for loop
  • Contents

  • for loop: The program below shows how to print out alphabets in a for loop:
     ####################################
    #Prints out all lower case alphabets
    
    letter = 'a'
    for i in range (0,26):
        print letter
        letter  = chr(ord(letter) + 1) 
  • while loop example The program below illustrates how to use while loop
     ############################################
    # Ensures that the user enters either of the 
    # characters (a, b or c)
    
    ## Gets input from th user
    message = raw_input("Please enter a, b, or c: ")
    
    while(message != "a" and message != "b" and message != "c"):
        message = raw_input("Please enter a, b, or c:")
    print "You entered: " + message