JavaScript RegExp-referentie
RegExp-object
Een reguliere expressie is een patroon van karakters.
Het patroon wordt gebruikt om "zoek-en-vervang" -functies op tekst uit te voeren om patronen te matchen.
In JavaScript is een RegExp-object een patroon met Eigenschappen en methoden .
Syntaxis
/pattern/modifier(s);
Voorbeeld
let pattern = /w3schools/i;
Voorbeeld uitgelegd:
w3schools | Het patroon om naar te zoeken |
---|---|
/w3scholen/ | Een reguliere expressie |
/w3schools/i | Een hoofdletterongevoelige reguliere expressie |
Lees onze JavaScript RegExp-zelfstudie voor een tutorial over reguliere expressies .
Browserondersteuning
/regexp/
is een ECMAScript1 (ES1)-functie.
ES1 (JavaScript 1997) wordt volledig ondersteund in alle browsers:
Chrome | IE | Edge | Firefox | Safari | Opera |
Yes | Yes | Yes | Yes | Yes | Yes |
Modifiers
Modifiers worden gebruikt om hoofdletterongevoelige en globale zoekopdrachten uit te voeren:
Modifier | Description |
---|---|
g | Perform a global match (find all matches rather than stopping after the first match) |
i | Perform case-insensitive matching |
m | Perform multiline matching |
Beugels
Haakjes worden gebruikt om een reeks tekens te vinden:
Expression | Description |
---|---|
[abc] | Find any character between the brackets |
[^abc] | Find any character NOT between the brackets |
[0-9] | Find any character between the brackets (any digit) |
[^0-9] | Find any character NOT between the brackets (any non-digit) |
(x|y) | Find any of the alternatives specified |
metakarakters
Metatekens zijn tekens met een speciale betekenis:
Metacharacter | Description |
---|---|
. | Find a single character, except newline or line terminator |
\w | Find a word character |
\W | Find a non-word character |
\d | Find a digit |
\D | Find a non-digit character |
\s | Find a whitespace character |
\S | Find a non-whitespace character |
\b | Find a match at the beginning/end of a word, beginning like this: \bHI, end like this: HI\b |
\B | Find a match, but not at the beginning/end of a word |
\0 | Find a NULL character |
\n | Find a new line character |
\f | Find a form feed character |
\r | Find a carriage return character |
\t | Find a tab character |
\v | Find a vertical tab character |
\xxx | Find the character specified by an octal number xxx |
\xdd | Find the character specified by a hexadecimal number dd |
\udddd | Find the Unicode character specified by a hexadecimal number dddd |
Kwantificatoren
Quantifier | Description |
---|---|
n+ | Matches any string that contains at least one n |
n* | Matches any string that contains zero or more occurrences of n |
n? | Matches any string that contains zero or one occurrences of n |
n{X} | Matches any string that contains a sequence of X n's |
n{X,Y} | Matches any string that contains a sequence of X to Y n's |
n{X,} | Matches any string that contains a sequence of at least X n's |
n$ | Matches any string with n at the end of it |
^n | Matches any string with n at the beginning of it |
?=n | Matches any string that is followed by a specific string n |
?!n | Matches any string that is not followed by a specific string n |
Eigenschappen RegExp-object
Property | Description |
---|---|
constructor | Returns the function that created the RegExp object's prototype |
global | Checks whether the "g" modifier is set |
ignoreCase | Checks whether the "i" modifier is set |
lastIndex | Specifies the index at which to start the next match |
multiline | Checks whether the "m" modifier is set |
source | Returns the text of the RegExp pattern |
RegExp-objectmethoden
Method | Description |
---|---|
compile() | Deprecated in version 1.5. Compiles a regular expression |
exec() | Tests for a match in a string. Returns the first match |
test() | Tests for a match in a string. Returns true or false |
toString() | Returns the string value of the regular expression |