8 useful regexps with a clear analysis of
About the power and flexibility of regular expressions written much, and their use has long been the standard for various types of operations on a text consisting of letters, numbers and service sivmolov. Perhaps the most regexps operate validation (verification) data entry - they are virtually no alternative, except bulky cyclic analysis functions with a bunch of non-obvious and obscure checks.
1. Part of the CNC (chelovekoponyatny URL)
pattern:
/ ^ [A-z0-9 -] + $ /
In fact, the word with hyphens.
2. The user will
pattern:
/ ^ [A-z0-9 _-] {3,16} $ /
Letters, numbers, hyphens, and underscores, from 3 to 16 characters.
3. Password
pattern:
/ ^ [A-z0-9 _-] {6,18} $ /
Same yuzerneym and only 6 to 18.
More succinctly - / ^ [\ w _] {6,18} $ /.
Similarly, for yuzerneym.
4. Hex color
pattern:
/ ^ # ([A-f0-9] {6} | [a-f0-9] {3})? $ /
The # (optional), then the word consisting of the letters a through f or numbers, length 3 or 6.
5. XML tag
pattern:
/^<([az]+)([^>]+)*(?:>(.*)<\/\1>|\s+\/>)$/
During the opening parenthesis <must be the word of the letters - the element name can then be attributes - any characters except the closing bracket>. Next - any text (content) and the closing tag, ie <Name />, or at least one space, slash and closed bracket (self-closing tag).
6. Email
pattern:
/^([a-z0-9_\.-]+)@([a-z0-9_\.-]+)\.([az\.]{2,6})$/
General view - логин@поддомен.домен. Login as a subdomain - words from letters, numbers, underscores, dashes and dots. A domain (meaning 1st level) - is from 2 to 6 letters and dots.
It can be shorter - /^([\w\._]+)@\1\.([az]{2,6}\.?)$/.
It is also a little more correct - a point in the domain of the first level can occur only once and only at the end.
7. URL
pattern:
/^(https?:\/\/)?([\da-z\.-]+)\.([az\.]{2,6})([\/\w \ .-] *) * \ /? $ /
First of all - the optional protocol (http: // or https: //), then the sequence of letters, numbers, hyphens, underscores and dots (domains level> 1), then the zero-level domain (from 2 to 6 letters and dots) and, finally, the file structure - a set of words from letters, numbers, hyphens, underscores and dots with a slash at the end. All this can be completed again slash.
The best way - /^(https?:\/\/)?([\w\.]+)\.([az]{2,6}\.?)(\/[\w\.]*) * \ /? $ /
8. IP address
pattern:
/ ^ (?: 25 [0-5] | 2 [0-4] [0-9] | [01] [0-9] [0-9]) \) {3} (25 ?: [0-?. 5] | 2 [0-4] [0-9] |?? [01] [0-9] [0-9]) $ /
4 groups of numbers (1 to 3 digits each) separated by periods. If the group consists of three characters, the first of which - one or two; if 1, then the remaining 0 to 9, and if the two - then a second from 0 to 5; if the second symbol from 0 to 4, the third - from 0 to 9, and when the second 5 - the third from 0 to 5. If the group consists of two characters, the first - from 1 to 9, the second - from 0 to 9 . In the case of single-character group with this symbol can be any number from 1 to 9.
So correct - / ^ (?
: 25 [0-5] | 2 [0-4] \ d | [01] \ d \ d) \) { 3} (25 ?: [0-5] | 2 [0-4]?. \ d | [01] \ d \ d) $ / ??.
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