1.4 Repeating statements with loops

Loops are used to repetitively execute a sequence of statements while changing a variable from iteration to iteration. This variable is called the index variable. It is successively assigned to the elements of a list:

L = [1, 2, 10]
for s in L:
    print(s * 2) # output: 2 4 20

The part to be repeated in the for loop has to be properly indented:

my_list = [...] # define a list
for elt in my_list:
    ...   #do_something
    ...   #something_else
print("loop finished") # outside the for block