Words and Numbers
What do you think happens when you try to do math with words?
> >> print 'red' + 'yellow'
redyellow
> >> print 'red' * 3
redredred
> >> print 'red' + 3
Traceback (most recent call last):
File "", line 1, in
TypeError: cannot concatenate 'str' and 'int' objects
> >>
If you add two words, it sticks them together. If you times a word by 3, it makes three copies.
Python doesn't know how to add a word and a number, so it says "cannot concatenate 'str' and 'int' objects." A word that you put in quotes is just a string of letters called a "str" in python. Numbers that don't have a decimal point are integers and are called "int" in python.
You can't add a str and an int. But you can turn a number into a string if you use the str() function.
> >> print 'red' + str(3)
red3
> >>
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