FOR LOOPS

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Python - For Loop

What is For Loop :

A for loop is used for iterating over a sequence (that is either a list, a tuple, a dictionary, a set, or a string).

This is less like the for keyword in other programming languages, and works more like an iterator method as found in other object-orientated programming languages.

With the for loop we can execute a set of statements, once for each item in a list, tuple, set etc.

Print each fruit in a fruit list:

x=["apple","banana","cherry"]
for i in x:
    print(i)

====o/p====
apple
banana
cherry

The for loop does not require an indexing variable to set beforehand.

Looping Through a String :

Even strings are iterable objects, they contain a sequence of characters.

for x in "banana":
    print(x)
    

=====o/p=====
b
a
n
a
n
a

The break Statement:

With the break statement we can stop the loop before it has looped through all the items.

Exit the loop when i is "banana":

x=["apple","banana","cherry"]
for i in x:
    print(i)
    if i == "banana":
     break
 
====o/p====
apple
banana

Exit the loop when i is "banana", but this time the break comes before the print.

x=["apple","banana","cherry"]
for i in x:
    if i == "banana":
     break
    print(i)

=====o/p=====
apple

The continue Statement :

With the continue statement we can stop the current iteration of the loop, and continue with the next.

x=["apple","banana","cherry"]
for i in x:
 if i == "banana":
       continue
 print(i)

====o/p====
apple
cherry

The range() Function :

To loop through a set of code a specified number of times, we can use the range() function.
The range() function returns a sequence of numbers, starting from 0 by default, and increments by 1 (by default), and ends at a specified number.

for x in range(10)
print(x)

====o/p====
0
1
2
3
4
5
6
7
8
9

( Note that range(10) is not the values of 0 to 10, but the values 0 to 9 ).

## The range() function defaults to 0 as a starting value, however it is possible to specify the starting value by adding a parameter: range(2, 9), which means values from 2 to 9 (but not including 9):

for x in range(2,9)
print(x)

====o/p====
2
3
4
5
6
7
8

## The range() function defaults to increment the sequence by 1, however it is possible to specify the increment value by adding a third parameter: range(2, 30, 3):

for x in range(2,20,3)
print(x)

====o/p====
2
5
8
11
14
17

("In the range, 3 indicates the difference between each number in the sequence")

Else in For Loop :

The else keyword in a for loop specifies a block of code to be executed when the loop is finished.

for i in range(6):
 print(i)
else:
     print("finally finished")
 
=====o/p=====
0
1
2
3
4
5
finally finished

Nested Loops :

A nested loop is a loop inside a loop.

The "inner loop" will be executed one time for each iteration of the "outer loop".

# print adjective for each fruit 

adj=["red","big","tasty"]
fruits=["apple","banana","cherry"]
for x in adj:
for y in fruits:
print(x,y)

====o/p=====
red apple
red banana
red cherry
big apple
big banana
big cherry
tasty apple
tasty banana
tasty cherry

The pass Statement :

for loops cannot be empty, but if we have a for loop with no content for some reason , put in the pass statement to avoid getting an error.

for x in [0,1,2]:
 pass 

====o/p====
>>>

[output gets as blank as we entered pass statement,if not we will get an error]