Lab 5: Loops

For Loops

What are they?

A for loop is similar to a while loop.
For loops are normally used when you want to repeat a section of code n number of times.

How do I use them?

• The syntax of a basic for loop is shown below:

for i in range(start, end, step):
    statements(s) 

The above loop would start executing with i = start. After each iteration, i will be incremented by the step . The loop will end when i >= end.

for i in range(0,10,3):
    print(i)
 

Output:
0
3
6
9


However, the only required argument is the end argument. The other two are optional.

for i in range (3):
    print(i)
 

Output:
0
1
2


for i in range (3, 8):
    print(i)
 

Output:
3
4
5
6
7


The step can be negative to iterate backwards.

for i in range (8, 3, -1):
    print(i)
 

Output:
8
7
6
5
4


You can iterate through strings as well in Python.

word = "hello"
for w in word:
    print(w)
 

Output:
h
e
l
l
o