Beginning Python - From Novice to Professional

24 CHAPTER 1 ■ INSTANT HACKING: THE BASICS
we don’t have to. It’s just convenient. An alternative is to use the backslash character (\) to
escape the quotes in the string, like this:
>>> 'Let\'s go!'
"Let's go!"
Python understands that the middle single quote is a character in the string and not the
end of the string. (Even so, Python chooses to use double quotes when printing out the string.)
The same works with double quotes, as you might expect:
>>> "\"Hello, world!\" she said"
'"Hello, world!" she said'
Escaping quotes like this can be useful, and sometimes necessary. For example, what would
you do without the backslash if your string contained both a single quote and a double quote,
as in the string 'Let\'s say "Hello, world!"'?
■Note Tired of backslashes? As you will see later in this chapter, you can avoid most of them by using long
strings and raw strings (which can be combined).
Concatenating Strings
Just to keep whipping this slightly tortured example, let me show you another way of writing
the same string:
>>> "Let's say " '"Hello, world!"'
'Let\'s say "Hello, world!"'
I’ve simply written two strings, one after the other, and Python automatically concatenates
them (makes them into one string). This mechanism isn’t used very often, but it can be useful
at times. However, it only works when you actually write both strings at the same time, directly
following one another:
>>> x = "Hello, "
>>> y = "world!"
>>> x y
SyntaxError: invalid syntax
In other words, this is just a special way of writing strings, not a general method of concatenating
them. How, then, do you concatenate strings? Just like you add numbers:
>>> "Hello, " + "world!"
'Hello, world!'
>>> x = "Hello, "
>>> y = "world!"
>>> x + y
'Hello, world!'