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Different Types of Loops in Python

Justin Bermudez
・1 min read

In this post I will show several loops in Python that you can utilize for your problems in python.

For Loop

For loop allows you to go over a dictionary, set, string, list, or tuple.

# loop over array example
array = [1, 2, 3, 4]
for x in array:
    print(x)

=> 1
=> 2
=> 3
=> 4

Loop Over String

string = "word"
for x in string:
    print(x)

=> w
=> o
=> r
=> d

Keep in mind, the printed out characters are of type string!

Loop over Set

Sets are unordered collections that have no duplicate elements

word = set("uniq")
for x in word:
    print(x)

=> u
=> n
=> i
=> q

Looping with range

Using range takes in a number to loop. You can use the length of an array for instance to iterate through the whole array.
Range will go by index so it will begin at 1 and end at the length - 1

array = [1, 2, 3, 4]
for i in range(len(array)):
    print("index:"i, ", value:", array[i])

=> index: 0 , value: 1
=> index: 1 , value: 2
=> index: 2 , value: 3
=> index: 3 , value: 4

While Loops

While loops continue to loop until the condition is met. Be careful using while loops because you can easily have an infinite loop.

counter = 0
while counter < 5:
    print(counter)
    counter += 1

=> 0
=> 1
=> 2
=> 3
=> 4

Not incrementing the counter here would result in an infinite loop and may timeout the program.

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