pythonregex

Gone with the Wind

Ben Gorman

Ben Gorman

Life's a garden. Dig it.

Here's a quote from Gone with the Wind 👫

quote = "Frankly my dear, I don't give a darn."

Check if it contains

  • a lowercase letter
  • followed by a single space
  • followed by the letter g

Expected result

Should return True.

quote = "Frankly my dear, I don'{==t g==}ive a darn."

Regex Functions

Function Description Return Value
re.findall(pattern, string, flags=0) Find all non-overlapping occurrences of pattern in string list of strings, or list of tuples if > 1 capture group
re.finditer(pattern, string, flags=0) Find all non-overlapping occurrences of pattern in string iterator yielding match objects
re.search(pattern, string, flags=0) Find first occurrence of pattern in string match object or None
re.split(pattern, string, maxsplit=0, flags=0) Split string by occurrences of pattern list of strings
re.sub(pattern, repl, string, count=0, flags=0) Replace pattern with repl new string with the replacement(s)

Regex Patterns

Pattern Description
[abc] a or b or c
[^abc] not (a or b or c)
[a-z] a or b ... or y or z
[1-9] 1 or 2 ... or 8 or 9
\d digits [0-9]
\D non-digits [^0-9]
\s whitespace [ \t\n\r\f\v]
\S non-whitespace [^ \t\n\r\f\v]
\w alphanumeric [a-zA-Z0-9_]
\W non-alphanumeric [^a-zA-Z0-9_]
. any character
x* zero or more repetitions of x
x+ one or more repetitions of x
x? zero or one repetitions of x
{m} m repetitions
{m,n} m to n repetitions
{m,n} m to n repetitions
\\, \., \* backslash, period, asterisk
\b word boundary
^hello starts with hello
bye$ ends with bye
(...) capture group
(po|go) po or go

Solution

import re
 
bool(re.search(pattern='[a-z]\sg', string=quote))
# True

Explanation

  1. a-z matches any lowercase character
  2. [a-z]\s matches any lowercase character, followed by a whitespace character
  3. [a-z]\sg matches any lowercase character, followed by a whitespace character, followed by the letter g

[re.search(pattern, string, ...)][re-search] scans the string looking for the first location where the regular expression pattern produces a match. If it finds a match, it returns a match object, otherwise it returns None.

re.search(pattern='[a-z]\sg', string=quote)
# <re.Match object; span=(23, 26), match='t g'>

Casting the result of re.search() to a boolean indicates whether a match was found.

bool(re.search(pattern='[a-z]\sg', string=quote))
# True