Fastest way to extract part of a long string in Python -

i have large set of strings, , looking extract part of each of strings. each string contains sub string this:

my_token:[   "key_of_interest" ], 

this part in each string says my_token. thinking getting end index position of ' my_token:[" ' , after getting beginning index position of ' "], ' , getting text between 2 index positions.

is there better or more efficient way of doing this? i'll doing string of length ~10,000 , sets of size 100,000.

edit: file .ion file. understanding can treated flat file - text based , used describing metadata.

how can can possibly done "dumbest , simplest way"?

• find starting position
• look on ending position
• grab indiscriminately between two

this indeed you're doing. further inprovement can come optimization of each step. possible ways include:

• narrow down search region (requires additional constraints/assumptions per comment56995056)
• speed search operation bits, include:
  • extracting raw data format
    • you did disregarding format altogether - have make sure there'll never incorrect parsing (e.g. search terms embedded in strings elsewhere or matching part of token) per comment56995034
  • elementary pattern comparison operation
    • unlikely attain in pure python since str.index implemented in c , implementation simple can possibly be