Question

I use the triple string in the following way:

str="""jeff"""
str=""""jeff"""
str=""""jeff""""   # error
str=""""jeff """"

The third one is error, could anyone explain why this is error ?

Answer 1

Three quotes terminate a string, so this

str=""""jeff""""

is parsed as this:

str= """ ("jeff) """ (")

The trailing quote is the problem.

BTW, looking at the BNF definition

longstring      ::=  "'''" longstringitem* "'''"
                     | '"""' longstringitem* '"""'

it’s obvious that the star * is non-greedy, I don’t know though if this is documented somewhere.

In response to the comment, this

 str = ''''''''jeff'''

is interpreted as

(''')(''')('')(jeff)(''') <-- error, two quotes

and this

 str = '''''''''jeff'''

is interpreted as

 str = (''')(''')(''')(jeff)(''') <-- no error, empty string + jeff