Split up regex

Author: lkollar

Lib/profiling/sampling/cli.py

@@ -288,7 +288,19 @@ def _run_with_sync(original_cmd, suppress_output=False):
         return process
 
 
-_RATE_PATTERN = re.compile(r'^(\d+(?:\.\d+)?)(hz|khz|k)?$', re.IGNORECASE)
+_RATE_PATTERN = re.compile(r'''
+      ^                   # Start of string
+      (                   # Group 1: The numeric value
+          \d+             #   One or more digits (integer part)
+          (?:\.\d+)?      #   Optional: decimal point followed by digits
+      )                   #   Examples: "10", "0.5", "100.25"
+      (                   # Group 2: Optional unit suffix
+          hz              #   "hz" - hertz
+          | khz           #   "khz" - kilohertz
+          | k             #   "k" - shorthand for kilohertz
+      )?                  #   Suffix is optional (bare number = Hz)
+      $                   # End of string
+  ''', re.VERBOSE | re.IGNORECASE)
 
 
 def _parse_sampling_rate(rate_str: str) -> int: