Python Day 54 – intro to regex

Went through some tutorials for regex today…

I learned:

  • \d can be used to replace any digit from 0 to 9
  • . is a wildcard
    • To use normal period. use \.
  • To specify characters use []
    • ex: [abc]an
      • To match any value that starts with a or b or c, and ends in ‘an’
    • To exclude, use [^abc]
    • Or use range [a-c]
  • To repetitions of characters
    • A{1,6} to signify how many repetitions
    • A+ one or more repetitions
    • A* zero or more repetitions
  • Optional characters
    • ?
  • White space characters
    • \s
    • \S (any non white space characters)
  • Starting and ending
    • ^…$
    • To cap off start and end values which helps prevent false positives (eg: unSUCCESSFUL)
  • Capturing a group
    • Use ()…
    • Can be useful for separating files from extension:
      • ^(file_name.+)\.png$

I’m still confused on:

For this dataset I’m practicing on I’m being asked to replace a letter in a string, however using the .str.replace(r”,”) function doesn’t seem to be working. I’ll continue this one tomorrow.

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