In python programming language, the
python 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.
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
============= 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.