Python - Need to delete everything before and after a variable in a string [closed]

Question

I am needing to read data out of a text file and locate certain fields contained within. I've gotten the txt file into a string but now I'm needing to locate certain fields. The file looks like:

City: New York

First Name: John

Last Name: Jones

Address: 123 Main St.

If I were wanting to pull the first name "John" out, what is the best way to do that in python? I know I can do a .find for "First Name: " but then how to I use that index to delete everything before and after "John" so I'm just left with a varialbe "John"

readData = open("data.txt", more='r')
rawData = readData.read()
readData.close()

x = rawData.index("First Name:")

Answer 1

Since you are using such a clean and regular format you can do this pretty easily by reading each line and splitting on : using str.split.

with open("some_file.txt") as file:
    for line in file:
        key, value, = line.split(": ", maxsplit=1)

or you can use a dictionary comprehension for a cleaner data structure representation:

with open("some_file.txt") as file:
    {key, value for key, value in [line.split(": ", maxsplit=1) for line in file]}

Note that you will probably also want to wrap these in a try-catch block to handle badly made or corrupted files where there is a missing key or missing value.

Answer 2

For storing this kind of data, i would really suggest using JSON; as it is very easy to use and versatile, here's an example:

data.json file:

{
  "city": "New York",
  "first_name": "John",
  "last_name": "Jones",
  "address": "123 Main St."
}

Python file:

import json #Python supports JSON from the get-go!
json_data = json.load(open("data.json"))

city = json_data['city']
first_name = json_data['first_name']
last_name = json_data['last_name']
address = json_data['last_name']

Answer 3

You could do it like this:

def main():
    with open("./data.txt", "r") as f:
        searched_key = "First Name"
        value = ""
        for line in f:
            if searched_key in line:
                value = line[len(searched_key) + 2:]

        print(value)

You should implement it as a function to be more handy. Just make searched_key a parameter and return value.

Also using jsons or dictionaries are easier and faster than txt.