How to extract the value between the brackets in Python

Question

I have a huge string and I am trying to parse it. What I want to do is read the clk (clock) values. Is there any way to extract this text(the text between the {[ ]}, in a Pythonic way?

1. e4 {[%clk 1:23:29]} c5 {[%clk 1:30:39]} 2. Nf3 {[%clk 1:23:32]} d6 {[%clk 1:30:58]} 3. d4 {[%clk 1:23:50]} cxd4 {[%clk 1:31:21]}

The goal is to take the clk values and store them in a list.

Answer 1

Assuming that you can't have bracketed values inside other bracketed values, it's easy enough to capture each bracketed value with regex:

import re

s = """1. e4 {[%clk 1:23:29]} c5 {[%clk 1:30:39]} 2. Nf3 {[%clk 1:23:32]} d6
{[%clk 1:30:58]} 3. d4 {[%clk 1:23:50]} cxd4 {[%clk 1:31:21]}"""

results = re.findall(r"{\[%clk (.*?)\]}", s)
print(results)

Result:

['1:23:29', '1:30:39', '1:23:32', '1:30:58', '1:23:50', '1:31:21']

Quick explanation of the regex pattern:

{       #literal curly bracket
\[      #literal square bracket
%clk    #literal "%clk "
(.*?)   #match any number of characters, and capture them for the output
\]      #literal square bracket
}       #literal curly bracket