For loop


#1

I am not able to understand the concept of for loop.
Please explain


#2

Basically a for loop can call on data and repeat instructions you make for what you want to do with the data.
For example:

data = ['hello', 'data', 'data types']
for strings in data:
print strings

strings is just a placeholder for the values in data.
That is my reasoning, someone correct me if I am wrong.