In python programming language, thepython for-each
loop is another variation of for loop
structure. In this loop structure, you get values from a list, set and assign it to a variable during each iteration.
It is little hard to understand without an example. Consider the usual way to using for loop.
for i in range(1,11):
print(i)
The above construct is useful and variable i
can be used as an index to a set or list and solve a problem.
Consider the following example.
my_list = [23, 66, 68, 88, 19]
sum = 0
# now we will use i as an index for the list items
for i in range(0,5):
sum = sum + my_list[i]
print(sum/5)
In the program above, the sum
is 0. The variable i used as index to my_list
and adds each item to sum during an iteration.
================ RESTART: C:\Python_projects\For-Each_Loop.py ================
52.8
>>>
The final value is sum of all number which is divided by 5 to get the average.
For-Each Loop
The for-each loop can be written as follows.
my_list = [55,66,77,88,99]
for list_item in my_list:
print(list_item)
The value of list is assigned to list_item
during the iteration and it printed in the next line.
================ RESTART: C:/Python_projects/For-Each_Loop.py ================
55
66
77
88
99
>>>
The for-each loop gives an opportunity to go through each item without skipping an member. The range of the loop depends on the set or the list.
A for-each loop can do everything that a traditional for loop can do. Consider the example, where we have modified the average finding program using for loop.
my_list = [55, 66, 77, 88, 99]
sum = 0
# take a sum of the numbers in the list
for list_item in my_list:
sum = sum + list_item
print(sum/5)
The program does everything that a traditional loop would do and take an average. The range()
function is replaced with the my_list
.
============= RESTART: C:\Python_projects\For-each_average_2.py =============
77.0
>>>
Note that the loop will run until it has finished adding each item to the sum.