Python - Control Structure - Loops - while and for

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Loops



Sometimes, you need to perform code on each item in a list. This is called iteration, and it can be accomplished with a while loop and a counter variable.
For example:
words = ["hello", "world", "spam", "eggs"]
counter = 0
max_index = len(words) - 1

while counter <= max_index:
word = words[counter]
print(word + "!")
counter = counter + 1

for Loop



Iterating through a list using a while loop requires quite a lot of code, so Python provides the forloop as a shortcut that accomplishes the same thing.
The same code from the previous example can be written with a for loop, as follows:
words = ["hello", "world", "spam", "eggs"]
for word in words:
print(word + "!")
The for loop in Python is like the foreach loop in other languages.

The for loop is commonly used to repeat some code a certain number of times. This is done by combining for loops with range objects.
for i in range(5):
print("hello!")
You don't need to call list on the range object when it is used in a for loop, because it isn't being indexed, so a list isn't required.





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