Regular Expressions in PHP quick reference

Expression	Will match…
text	the string “text”
^text	“text” at the start of a line
text$	“text” at the end of a line
^text$	“text” when it is alone on a line
[Tt]ext	“Text” or “text”
[abc]	a, b, or c
[^abc]	d, e, f, g, h, etc – everything that is not a, b, or c (^ is “not” inside sets)
[A-Z]	any uppercase letter
[a-z]	any lowercase letter
[A-Za-z]	any letter
[A-Za-z0-9]	any letter of number
[A-Z]+	one or more uppercase letters
[A-Z]*	zero or more uppercase letters
[A-Z]?	zero or one uppercase letters
[A-Z]{3}	3 uppercase letters
[A-Z]{3,}	a minimum of 3 uppercase letters
[A-Z]{1,3}	1-3 uppercase letters
[^0-9]	any non-numeric character
[^0-9A-Za-z]	any symbol (not a number or a letter)
Fo*	F, Fo, Foo, Fooo, Foooo, etc
Fo+	Fo, Foo, Fooo, Foooo, etc
Fo?	F, Fo
.	any character except \n (new line)
\b	a word boundary. E.g. te\b matches the “te” in “late”, but not the “te” in “tell”.
\B	a non-word boundary. “te\B” matches the “te” in “tell” but not the “te” in “late”.
\n	new line character
\s	any whitespace (new line, space, tab, etc)
\S	any non-whitespace character

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