python - Single quoted string vs. double quoted string

Question

Why do we need an escape character for single quoted string, but not for a double quoted string?

a = 'hello how's it going'
a1 = 'hello how's it going'
b =  "hello how's it going"

assert(a==b) # Passes

assert(a1==b) # Errors

The error message:

 File "string.py", line 1
    a = 'hello how's it going'
                  ^
SyntaxError: invalid syntax

Answer 1

It doesn't matter if you use ' or " around the string to mark it as string literal. But you can't use that character inside the string literal without escaping it using a in front of it - otherwise Python interprets it as the end of the string.

For example " inside a " delimited string literal need to be escaped as well:

a = "And he said: "What a nice day"."