[cmdlhz’s 2019 Self-leaching Story] Series
[JavaScript]
🌱 Net Ninja - JavaScript ES6
🌱 Net Ninja - Asynchronous JavaScript
🌱 Net Ninja - Object Oriented JavaScript
🌱 Coding Train - JavaScript ES6-ES8 (Part1, Part2)[Regular Expressions]
🌱 Coding Train - Programming with Text[Vue]
🌱 Net Ninja - Vue CLI3
🌱 Net Ninja - Vue JS2
🌱 Net Ninja - Vuex
🌱 Net Ninja - Vuetify (Part1, Part2, Part3)[Python/Django]
🌱 Net Ninja - Python3
🌱 Net Ninja - Django[Figma]
🌱 Design Course
🌱 Figma (Part1, Part2, Part3, Part4, Part5)[Illustrator]
🌱 TastyTuts (Part1, Part2, Part3)[SQL]
🌱 freeCodeCamp
🌱 This is my summary of Coding Train’s “Regular Expressions — Programming with Text” on YouTube.
[1. Intro]
[2. Meta-characters]
[3. Character Classes]
[4. Capturing Groups]
[5. Back References]
[6. test() & match()]
[7. exec()]
[8. split()]
[9. replace()]
[ 2. Meta-characters ]
https://regex101.com/ : Test regular expressions and check out quick reference.
Some of meta-characters are the following:
TYPE 1: Single Characters
. : Matches any character other than newline (or including newline with the /s flag).
\s : Matches any space, tab or newline character.
\S : Matches anything other than a space, tab or newline.
\d : Matches any decimal digit. Equivalent to [0–9].
\D : Matches anything other than a decimal digit.
\w : Matches any letter, digit or underscore. Equivalent to [a-zA-Z0–9_].
\W : Matches anything other than a letter, digit or underscore.
(a|b) : Matches the a or the b part of the subexpression.
\ : This may be used to match the literal value of any meta-character, or the / delimiter.
TYPE 2: Quantifiers
a* : Matches zero or more consecutive `a` characters.
a+ : Matches one or more consecutive `a` characters.
a? : Matches an `a` character or nothing.
a{3} : Matches exactly 3 consecutive `a` characters.
a{3,} : Matches at least 3 consecutive `a` characters.
a{3,6} : Matches between 3 and 6 (inclusive) consecutive `a` characters.
TYPE 3: Position
^ : Matches the start of a string without consuming any characters. If multiline mode is used, this will also match immediately after a newline character.
$ : Matches the end of a string without consuming any characters. If multiline mode is used, this will also match immediately before a newline character.
\b : Matches, without consuming any characters, immediately between a character matched by \w and a character not matched by \w (in either order). It cannot be used to separate non words from words.
TYPE 4: Flags
g : Tells the engine not to stop after the first match has been found, but rather to continue until no more matches can be found.
m : The ^ and $ anchors now match at the beginning/end of each line respectively, instead of beginning/end of the entire string.
i : A case insensitive match is performed, meaning capital letters will be matched by non-capital letters and vice versa.
[ 3. Character Classes ]
[abc] : Matches either an a, b or c character
[a-z] : Matches any characters between a and z, including a and z.
[^a-z] : Matches any characters except those in the range a-z.
EXAMPLE :
[ 4. Capturing Groups ]
You can group regular expressions and replace them.
EXAMPLE 1 :
EXAMPLE 2 :
EXAMPLE 3 :
[ 5. Back References ]
>>> Back reference allows us to find a repeat of an earlier part of the capturing group.
[ 6. test() & match() ]
“The test() method executes a search for a match between a regular expression and a specified string. Returns true or false” (MDN).
“The match() method retrieves the result of matching a string against a regular expression” (MDN).
[ 8. split() ]
[ 9. replace() ]
EXAMPLE 1 :
EXAMPLE 2 :
Thanks for reading! 🎵 If you like this blog post, please clap👏
