 # Python For Loop

If you are here, it means you are going to be a coder soon. You will solve real-world computer problems, make your own programs, and a lot more. Yeah, sounds good!

Now let's talk about for. It is also a loop like while. Let's see how it works.

## Python for Loop

### Python for loop Syntax

for iter in sequence:
statement
statement
...


sequence is a sequence like list, tuple, string, etc. iter is a variable that takes the value of each item in the sequence. The body of the for loop consists of all the indented statements below for iter in sequence:. ### Python for loop Examples

colors = ["Blue", "Green", "Yellow", "Orange", "Red", "Brown"]
for color in colors:
print(color)

Blue
Green
Yellow
Orange
Red
Brown

By looking at the output, you might have got some idea of what the for loop does. Let’s understand the code.

colors is a list here containing six items.

for color in colorscolor is a variable which goes to each element in the list colors and takes its value.

So, in the first iteration, color is equal to the 1st element of the list. In the second iteration, color is equal to the 2nd element of the list, and so on.

Therefore, in the first iteration, the value of color is “Blue” and so print(color) printed Blue. Similarly, in the second iteration, Green got printed, and so on. Notice that the body of for loop is also represented by equal indentation (margin) from the left.

#### Python Example of Sum of Marks using Loop

marks = [78, 98, 50, 37, 45]
sum = 0
for m in marks:
sum = sum + m
print(sum)

308

You must have understood the code. If not, then let us explain a bit.

sum = 0 → We are taking a variable sum and assigning it an initial value of 0.

In the 1st iteration, m is 78. So, sum + m (0 + 78 = 78) makes the value of sum as 78.

In the 2nd iteration, m is 98. So, sum + m (78 + 98 = 176) makes the value of sum as 176.

After all the iterations, sum becomes 308.

We will look at the use of for loop with lists, strings, tuples and other sequences in detail in later chapters.

## Python range() function

The range() function is used to generate a sequence of numbers.

### Python range Syntax

range(start, stop, step_size)


start - Integer from which the sequence starts. It is optional. Its default value is 0.

stop - Integer before which the sequence stops. It is mandatory.

step_size - Increment between each integer in the sequence. It is optional. Its default value is 1.

range(10) generates ten integers starting from 0 to 9. Here, start = 0, stop = 10, step_size = 1.

range(1, 10) generates nine integers starting from 1 to 9. Here, start = 1, stop = 10, step_size = 1.

range(1, 10, 2) generates the integers 1, 3, 5, 7, 9. Here, start = 1, stop = 10, step_size = 2. ### Python range Examples

In the last chapter, we printed the first 10 natural numbers using a while loop. Let’s do that using a for loop.

for n in range(1, 11):
print(n)

1
2
3
4
5
6
7
8
9
10

The next example prints the multiplication table of 14 using a for loop.

for i in range(1, 11):
print(i*14)

14
28
42
56
70
84
98
112
126
140

Now let’s print all the even numbers from 10 (included) to 20 (included).

for num in range(10, 21, 2):
print(num)

10
12
14
16
18
20

That was cool, right? We could print the desired results using just 2 lines of code. We suggest you practice more questions on loops from our practice section.

To learn from simple videos, you can always look at our Python video course on CodesDope Pro. It has over 500 practice questions and over 20 projects.
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