PHP - How to write a regex to check that a string only contains certain characters?

Question

I have little to no experience in writing regular expressions. How would I go about checking that a string contains only zeros, spaces, hyphens, and colons? Thanks!

Answer 1

You should get good performance using a simple regex (no forward lookups):

^[0 :-]++$

Breaking it down:

• ^ recognizes the beginning of the input
• [] means that any character within the brackets matches.
• + means that the preceding (the brackets) must match 1 or more times. ++ makes it possesive , improving performance.
• $ recognizes the end of the input

Answer 2

/^[0\s:-]+$/ 

• ^ = start of string
• [0\\s:-]+ = one or more zeros, spaces, hyphens, colon. The + means one or more , \\s is any whitespace character, which may include line breaks and tabs.
• $ = end of string

Since the pattern is anchored between ^ and $ , no characters other than those in the [] character class will match.

If instead of any whitespace character, you permit only a literal space, use:

/^[0 :-]+$/ 

Answer 3

您可以使用范围。

^[0 \-:]{1,}$