Lesson 6 - Loops - Conditions

  • Python Loops
    If you want to iterate through all the elements of a list or a dictionary, python lets you do this with 
    two primitive loop commands:

    • while loops
    • for loops

    The while Loop

    Within the while loop,  as long as a condition is true, the set of statements are executed


    Print x as long as count is less than 5:

    count = 1
    while count < 6:
      count += 1

    The for Loop

    for loop is used for iterating over a sequence (i.e a list, a tuple, a dictionary, a set, or a string).

    Example1: Print each fruit in a fruit list:
    fruits = [“apple”“banana”“kiwi”]
    for x in fruits:

    Example2: Print all the keys in a dictionary:
    report={“subject”:”Maths”, “grade”: “A”,”marks”:99}

    for x in report:

    Example3: Print all the valuess in a dictionary:
    report={“subject”:”Maths”, “grade”: “A”,”marks”:99}
    for x in report.values():

    Conditions –  If … Else

    You would use several conditions in your programming. Python supports the usual logical conditions from mathematics:

    • Equals: a == b
    • Not Equals:  a != b
    • Less than:  a < b
    • Less than or equal to:  a <= b
    • Greater than: a > b
    • Greater than or equal to: a >= b

    These conditions can be used in several ways, most commonly in “if statements” and loops.

    An “if statement” is written by using the if keyword,  “else statement” by else keyword


    a = 45
    b = 33

    if b > a:
      print(“b is greater than a”)
      print(“b is not greater than a”)

     elif  condition  (elseif)


    a = 85
    b = 63

    if b > a:
      print(“b is greater than a”)
    elif b==a:
      print(“b is equals to a”)
      print(“b is less than a”)




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


    Exit the loop when x is 3:

    x = 1
    while x < 5:
       if x == 3:
       x += 1

    The continue statement

    This will print 1,2,4,5,6.  if the i == 3, the continue  of the loop will be invoked skipping the print of 3
    i = 0

    while i < 6:
      i += 1
      if i == 3: