Inserting braces with format in python

Question

I am trying to print this string

str = "container.insert({{ {0} ,{{ {{ {1}, {{ {2} ,{3} ,{4} , {5} }} }} }} }});"
str.format(prim_ident,country_ident,final[0],final[1],final[2],final[3])
fileWrite.write(str)

However the output of above that I get is

container.insert({{ {0} ,{{ {{ {1}, {{ {2} ,{3} ,{4} , {5} }} }} }} }});

Two problems the first problem is that i am getting double curly braces. I only want to show a single curly brace. But i read that you have to use double curly braces when u would like the curly brace to be present in the string the other problem is my format is not working (i.e) {0},{1} etc are not being replaced by their equivalent values. Can anyone please tell me what I am doing wrong ?

Answer 1

str.format() does modify the string in-place, you still need to save it to a variable, try adding str = :

str = str.format(prim_ident,country_ident,final[0],final[1],final[2],final[3])