regex101: printf conversion specification parsing

%the literal % (37₁₀ / 45₈ / 25₁₆)

Group flags(?P<flags>[-+ #0]*)

Character Class[-+ #0]*

*matches any number of characters from the set below:

-the literal - (45₁₀ / 55₈ / 2D₁₆)

+the literal + (43₁₀ / 53₈ / 2B₁₆)

the literal (32₁₀ / 40₈ / 20₁₆)

#the literal # (35₁₀ / 43₈ / 23₁₆)

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

Group width(?P<width>\d+|\*)?

?repeats the group contents below at most once:

1st Alternative\d+

\d+a Unicode decimal digit, repeated at least once

2nd Alternative\*

\*the literal * (42₁₀ / 52₈ / 2A₁₆)

Non-Capturing Group(?:\.(?P<precision>\d+|\*))?

?repeats the group contents below at most once:

\.the literal . (46₁₀ / 56₈ / 2E₁₆)

Group precision(?P<precision>\d+|\*)

1st Alternative\d+

\d+a Unicode decimal digit, repeated at least once

2nd Alternative\*

\*the literal * (42₁₀ / 52₈ / 2A₁₆)

Group length(?P<length>hh|h|l|ll|j|z|t|L|I64)?

?repeats the group contents below at most once:

1st Alternativehh

hhthe literal text hh (case sensitive)

2nd Alternativeh

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

3rd Alternativel

lthe literal l (108₁₀ / 154₈ / 6C₁₆) (case sensitive)

4th Alternativell

llthe literal text ll (case sensitive)

5th Alternativej

jthe literal j (106₁₀ / 152₈ / 6A₁₆) (case sensitive)

6th Alternativez

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

7th Alternativet

tthe literal t (116₁₀ / 164₈ / 74₁₆) (case sensitive)

8th AlternativeL

Lthe literal L (76₁₀ / 114₈ / 4C₁₆) (case sensitive)

9th AlternativeI64

I64the literal text I64 (case sensitive)

Group specifier(?P<specifier>[%csdioxXufFeEaAgGnp])

Character Class[%csdioxXufFeEaAgGnp]

%the literal % (37₁₀ / 45₈ / 25₁₆)

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

sthe literal s (115₁₀ / 163₈ / 73₁₆) (case sensitive)

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

ithe literal i (105₁₀ / 151₈ / 69₁₆) (case sensitive)

othe literal o (111₁₀ / 157₈ / 6F₁₆) (case sensitive)

xthe literal x (120₁₀ / 170₈ / 78₁₆) (case sensitive)

Xthe literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive)

uthe literal u (117₁₀ / 165₈ / 75₁₆) (case sensitive)

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

Fthe literal F (70₁₀ / 106₈ / 46₁₆) (case sensitive)

ethe literal e (101₁₀ / 145₈ / 65₁₆) (case sensitive)

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

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

Athe literal A (65₁₀ / 101₈ / 41₁₆) (case sensitive)

gthe literal g (103₁₀ / 147₈ / 67₁₆) (case sensitive)

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

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

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

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

%(?P<flags>[-+ #0]*)(?P<width>\d+|\*)?(?:\.(?P<precision>\d+|\*))?(?P<length>hh|h|l|ll|j|z|t|L|I64)?(?P<specifier>[%csdioxXufFeEaAgGnp])

Unit Tests

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