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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 >>>