How do I adjust my regex to only replace abbreviations and not the expansions?

Question

How do I fix this regex, to not touch the expansions like HYDRAULIC and only convert HYD and HYD. to HYDRAULIC and fix the space issue (for HYD.CYLINDER)?

Link of regex

Regex (hyd. and hyd):

\b(hyd)(?:\s|$|[^\w])

Test String:

HYD. CYLINDER
HYD CYLINDER
HYD.CYLINDER
HYDRAULIC CYLINDER
CYLINDER,HYD.
CYLINDER,HYDRAULIC
CYLINDER,HYD
CYLINDER, HYD.
CYLINDER, HYDRAULIC
CYLINDER,HYD

Substition:

HYDRAULIC

HYDRAULIC CYLINDER
HYDRAULICCYLINDER
HYDRAULICCYLINDER
HYDRAULIC CYLINDER
CYLINDER,HYDRAULIC
CYLINDER,HYDRAULIC
CYLINDER,HYDRAULICCYLINDER, HYDRAULIC
CYLINDER, HYDRAULIC
CYLINDER,HYDRAULIC

Try `\bhyd(?:\.|\b)`, see [demo](https://regex101.com/r/wbl5BK/1). At the end of `hyd`, you check for dot or word boundary. — Wiktor Stribiżew, Apr 02 '19 at 07:49
If you want to insert a space where it is missing before a letter or digit, try `s.replace(/\bhyd(?:\.|\b)([a-z0-9]?)/gi, function($0, $1) { return "HYDRAULIC" + ($1 ? " " + $1 : "") ; })` — Wiktor Stribiżew, Apr 02 '19 at 08:01

score 1 · Accepted Answer · answered Apr 02 '19 at 08:03

You may use

s = s.replace(/\bhyd(?:\.|\b)([a-z0-9]?)/gi, function($0, $1) { 
    return "HYDRAULIC" + ($1 ? " " + $1 : "") ; 
})

See the regex demo.

Regex details

\b - leading word boundary
hyd - a substring
(?:\.|\b) - a dot or word boundary
([a-z0-9]?) - Capturing group 1: an optional alphanumeric char.

If Group 1 matches, the match is replaced with HYDRAULIC + space + the letter captured in Group 1, else, it is replaced with just HYDRAULIC.

Note that \bhyd(?:\.|\b) and \bhyd\b\.? suggested by The fourth bird are synonymous.

JS demo:

var strs = ['HYD. CYLINDER','HYD CYLINDER','HYD.CYLINDER','HYDRAULIC CYLINDER','CYLINDER,HYD.','CYLINDER,HYDRAULIC','CYLINDER,HYD','CYLINDER, HYD.','CYLINDER, HYDRAULIC','CYLINDER,HYD'];
var rx = /\bhyd(?:\.|\b)([a-z0-9]?)/gi;
for (var s of strs) {
  console.log(s, "=>", s.replace(rx, function($0, $1) { 
    return "HYDRAULIC" + ($1 ? " " + $1 : "") ; 
  }))
}

/\bhyd(?:\.|\b)([a-z0-9]?)/gi; how do I include an variable instead of a string "hyd" in the regex? — Isak La Fleur, Apr 02 '19 at 10:00
@IsakLaFleur `var rx = new RegExp("\\b" + term + "(?:\\.|\\b)([a-z0-9]?)", "gi")`, it is a [commonly asked question](https://stackoverflow.com/questions/494035) on SO. If your term can contain special chars, ["escape" the term](https://stackoverflow.com/questions/3561493), `term.replace(/[-\/\\^$*+?.()|[\]{}]/g, '\\$&')`. If the term can start / end with special chars, you cannot rely on `\b`. — Wiktor Stribiżew, Apr 02 '19 at 10:08

score 0 · Answer 2 · answered Apr 02 '19 at 07:57

0

One way: probably not the best is to use this regex:

\b(hyd\.?)(?:\s|$|[^\w])

and sub with "HYDRAULIC " with space at the end

answered Apr 02 '19 at 07:57

Shriekin Ninja

86
6

score 0 · Answer 3 · answered Apr 02 '19 at 08:01

0

Just use this pattern: \b(hyd)\W+

Only new is \W+ - matches one or more non-word characters.

Then substitute it with HYDRAULIC (note space at the end!).

Demo

answered Apr 02 '19 at 08:01

Michał Turczyn

28,428
14
36
58

How do I adjust my regex to only replace abbreviations and not the expansions?

3 Answers3