regex101: Dimensioned quantities in markdown, selected units

Non-Capturing Group(?:^|\b)

1st Alternative^

^start of line

2nd Alternative\b

\ban ASCII word boundary

Group number(?<number>(?:\d+|\d{1,3}(?:,\d{3})+)(?:\.\d+)?)

Non-Capturing Group(?:\d+|\d{1,3}(?:,\d{3})+)

1st Alternative\d+

\d+a digit, repeated at least once

2nd Alternative\d{1,3}(?:,\d{3})+

\d{1,3}a digit, repeated between 1 and 3 times

Non-Capturing Group(?:,\d{3})+

+repeats the group contents below at least once:

,the literal , (44₁₀ / 54₈ / 2C₁₆)

\d{3}a digit, repeated exactly 3 times

Non-Capturing Group(?:\.\d+)?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

\d+a digit, repeated at least once

Group replace(?<replace> ?|&[^;]{2,7};)

1st Alternative ?

?optionally matches the literal (32₁₀ / 40₈ / 20₁₆)

2nd Alternative&[^;]{2,7};

&the literal & (38₁₀ / 46₈ / 26₁₆)

Negated Character Class[^;]{2,7}

{2,7}matches between 2 and 7 characters outside the set below:

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

Group dimensions(?<dimensions>(?<mathjax>\$[^\n\$]+\$)|(?<unit>(?<si>(?!as)(?:[QRYZEPTGMkhdcmµnpfazyrq]|da)?(?:mol|cd|Hz|Pa|Wb|lm|lx|Bq|Gy|Sv|kat|[mgsAKNJWCVFΩSTHL]))|(?<imperial>mil|P|in|ft|yd|mi|le|ftm|nmi|oz|lbs?|t|tsp|tbsp|c|fl oz|pt|qt|gal|(?:sq|cu) ?(?:in|ft|yd|mi)|ft-lbf?|lbf?-ft|deg|Btu|psi|Ly)|(?<common>mph|kph|rad|sr)|(?<binary>(?:(?:[KMGTPEZY])i?)?B)))

1st Alternative(?<mathjax>\$[^\n\$]+\$)

Group mathjax(?<mathjax>\$[^\n\$]+\$)

\$the literal $ (36₁₀ / 44₈ / 24₁₆)

Negated Character Class[^\n\$]+

+matches at least one character outside the set below:

\na line-feed (newline) character (ASCII 10)

\$the literal $ (36₁₀ / 44₈ / 24₁₆)

2nd Alternative(?<unit>(?<si>(?!as)(?:[QRYZEPTGMkhdcmµnpfazyrq]|da)?(?:mol|cd|Hz|Pa|Wb|lm|lx|Bq|Gy|Sv|kat|[mgsAKNJWCVFΩSTHL]))|(?<imperial>mil|P|in|ft|yd|mi|le|ftm|nmi|oz|lbs?|t|tsp|tbsp|c|fl oz|pt|qt|gal|(?:sq|cu) ?(?:in|ft|yd|mi)|ft-lbf?|lbf?-ft|deg|Btu|psi|Ly)|(?<common>mph|kph|rad|sr)|(?<binary>(?:(?:[KMGTPEZY])i?)?B))

Group unit(?<unit>(?<si>(?!as)(?:[QRYZEPTGMkhdcmµnpfazyrq]|da)?(?:mol|cd|Hz|Pa|Wb|lm|lx|Bq|Gy|Sv|kat|[mgsAKNJWCVFΩSTHL]))|(?<imperial>mil|P|in|ft|yd|mi|le|ftm|nmi|oz|lbs?|t|tsp|tbsp|c|fl oz|pt|qt|gal|(?:sq|cu) ?(?:in|ft|yd|mi)|ft-lbf?|lbf?-ft|deg|Btu|psi|Ly)|(?<common>mph|kph|rad|sr)|(?<binary>(?:(?:[KMGTPEZY])i?)?B))

1st Alternative(?<si>(?!as)(?:[QRYZEPTGMkhdcmµnpfazyrq]|da)?(?:mol|cd|Hz|Pa|Wb|lm|lx|Bq|Gy|Sv|kat|[mgsAKNJWCVFΩSTHL]))

Group si(?<si>(?!as)(?:[QRYZEPTGMkhdcmµnpfazyrq]|da)?(?:mol|cd|Hz|Pa|Wb|lm|lx|Bq|Gy|Sv|kat|[mgsAKNJWCVFΩSTHL]))

Negative Lookahead(?!as)

asthe literal text as (case sensitive)

Non-Capturing Group(?:[QRYZEPTGMkhdcmµnpfazyrq]|da)?

?repeats the group contents below at most once:

1st Alternative[QRYZEPTGMkhdcmµnpfazyrq]

Character Class[QRYZEPTGMkhdcmµnpfazyrq]

Qthe literal Q (81₁₀ / 121₈ / 51₁₆) (case sensitive)

Rthe literal R (82₁₀ / 122₈ / 52₁₆) (case sensitive)

Ythe literal Y (89₁₀ / 131₈ / 59₁₆) (case sensitive)

Zthe literal Z (90₁₀ / 132₈ / 5A₁₆) (case sensitive)

Ethe literal E (69₁₀ / 105₈ / 45₁₆) (case sensitive)

Pthe literal P (80₁₀ / 120₈ / 50₁₆) (case sensitive)

Tthe literal T (84₁₀ / 124₈ / 54₁₆) (case sensitive)

Gthe literal G (71₁₀ / 107₈ / 47₁₆) (case sensitive)

Mthe literal M (77₁₀ / 115₈ / 4D₁₆) (case sensitive)

kthe literal k (107₁₀ / 153₈ / 6B₁₆) (case sensitive)

hthe literal h (104₁₀ / 150₈ / 68₁₆) (case sensitive)

dthe literal d (100₁₀ / 144₈ / 64₁₆) (case sensitive)

cthe literal c (99₁₀ / 143₈ / 63₁₆) (case sensitive)

mthe literal m (109₁₀ / 155₈ / 6D₁₆) (case sensitive)

µthe literal µ (181₁₀ / 265₈ / B5₁₆) (case sensitive)

nthe literal n (110₁₀ / 156₈ / 6E₁₆) (case sensitive)

pthe literal p (112₁₀ / 160₈ / 70₁₆) (case sensitive)

fthe literal f (102₁₀ / 146₈ / 66₁₆) (case sensitive)

athe literal a (97₁₀ / 141₈ / 61₁₆) (case sensitive)

zthe literal z (122₁₀ / 172₈ / 7A₁₆) (case sensitive)

ythe literal y (121₁₀ / 171₈ / 79₁₆) (case sensitive)

rthe literal r (114₁₀ / 162₈ / 72₁₆) (case sensitive)

qthe literal q (113₁₀ / 161₈ / 71₁₆) (case sensitive)

2nd Alternativeda

Non-Capturing Group(?:mol|cd|Hz|Pa|Wb|lm|lx|Bq|Gy|Sv|kat|[mgsAKNJWCVFΩSTHL])

2nd Alternative(?<imperial>mil|P|in|ft|yd|mi|le|ftm|nmi|oz|lbs?|t|tsp|tbsp|c|fl oz|pt|qt|gal|(?:sq|cu) ?(?:in|ft|yd|mi)|ft-lbf?|lbf?-ft|deg|Btu|psi|Ly)

3rd Alternative(?<common>mph|kph|rad|sr)

4th Alternative(?<binary>(?:(?:[KMGTPEZY])i?)?B)

Positive Lookahead(?=\b|$| |[.,:;()\[\]{}=/*+—–-])

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Search reference

Regular Expression

(?:^|\b)(?<number>(?:\d+|\d{1,3}(?:,\d{3})+)(?:\.\d+)?)(?<replace> ?|&[^;]{2,7};)(?<dimensions>(?<mathjax>\$[^\n\$]+\$)|(?<unit>(?<si>(?!as)(?:[QRYZEPTGMkhdcmµnpfazyrq]|da)?(?:mol|cd|Hz|Pa|Wb|lm|lx|Bq|Gy|Sv|kat|[mgsAKNJWCVFΩSTHL]))|(?<imperial>mil|P|in|ft|yd|mi|le|ftm|nmi|oz|lbs?|t|tsp|tbsp|c|fl oz|pt|qt|gal|(?:sq|cu) ?(?:in|ft|yd|mi)|ft-lbf?|lbf?-ft|deg|Btu|psi|Ly)|(?<common>mph|kph|rad|sr)|(?<binary>(?:(?:[KMGTPEZY])i?)?B)))(?=\b|$| |[.,:;()\[\]{}=/*+—–-])

New

I have a 30 $m^2$ pumpernickle
More precisely it's 29.87$m^2$.
Traveling over 4,000 km, to where once there was
...in the year 2016 as a new method of...
He crashed at 50mph
They collided at speeds of over 200m/s
The reading is 2kHz.
The range is 20kHz–1MHz (1,000.3 kHz).
Just 4M words at 30MB.

Substitution

$<number>&#x202f;$<dimensions>