I'm trying to write a regex code so that it can fit the following criteria:

• CS 1110: "Introduction to Programming"
• ENGR 1624: "Introduction to Engineering"
• BME 2220: "Biomechanics"

should all match.

• CS 20: "Introduction to CS"
• ENGR 1624: " "
• ENGR 1624: ""

should not match.

This is my code so far:

([A-Z]{2,4})\s([1000-4000]{4})(:)\s(["][a-zA-Z]*\s[a-zA-Z]*?\s[a-zA-Z]*["])

However I'm running into two problems:

1. When I try to run ENGR 1624, it is not working (I assume because the [1000-4000]{4} part of my code is wrong)
2. It will not work for just the one word "Biomechanics"

Can anyone help fix my code please???

CodePudding user response：

If you don't want to match an empty string between the last parenthesis, you can repeat the character class 1 or more times [a-zA-Z] and optionally repeat a group starting with a space and again the character class.

About the notations in the pattern, the " does not have to be between square brackets, the character class notation [1000-4000]{4} is not a range, it repeats 4 times any of 0 1 - and 4

A range from 1000-4000 can be written as (?:4000|[1-3][0-9]{3}) which matches either 4000 or a range from 1000 - 3999

You might update the pattern using 3 capture groups instead:

\b([A-Z]{2,4})\s(4000|[1-3][0-9]{3}):\s("[a-zA-Z] (?:\s[a-zA-Z] )*")

Regex demo | Python demo

For example

import re

pattern = r'\b([A-Z]{2,4})\s(4000|[1-3][0-9]{3}):\s("[a-zA-Z] (?:\s[a-zA-Z] )*")'

s = ("CS 1110: \"Introduction to Programming\", ENGR 1624: \"Introduction to\n"
    "Engineering\", and BME 2220: \"Biomechanics\"\n\n"
    "CS 20: \"Introduction to CS\", ENGR 1624: \" \", and ENGR 1624: \"\"")

print(re.findall(pattern, s))

Output

[('CS', '1110', '"Introduction to Programming"'), ('ENGR', '1624', '"Introduction to\nEngineering"'), ('BME', '2220', '"Biomechanics"')]