PHP regular expressions

PHP regular expressions

1. Write a function to verify that the email format is correct.

Function checkemail ($ email ){

Echo preg_match ('/^ [w] + @ [w] + [.] ([w] +) $/', $ email )? 'Email format is correct ': 'Incorrect email format ';

        }

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2. Write a regular expression to overwrite all JS/VBS scripts on the web page (that is, remove the script tag and its content ):

Preg_replace ("/<script [^>]. *?>. *? </Script>/si "," newinfo ", $ script );

3. Write the regular expression that matches the URL.

/^ [A-zA-z] +: // (w + (-w +) *) (. (w + (-w + )*))*(? S *)? /Powerful

/^ Http: // www. ([w] +). ([w] +) $/weak
  

4. Verify the regular expression of the 11-digit mobile phone number starting with 139

Preg_match (/^ 139 [0-9] {8} $ /)

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4. Write at least one regular expression for verifying 11 mobile phone numbers.

Preg_match ("/^ 13 [0-9] {1} [0-9] {8} $ /")

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5. Write a regular expression to express the integers and floating-point numbers in PHP.

/^ (0 | [1-9] d *) ([.] 5 )? $/

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6. Use a regular expression to write a function to verify that the IP address format is correct?

/A ([0-9]? [0-9]) | (1 [0-9] {2}) | (2 [0-4] [0-9]) | (25 [0-5]).) {3} ([0-9]? [0-9]) | 1 [0-9] {2}) | (2 [0-4] [0-9]) | (25 [0-5]) Z/

Error

/^ (25 [0-5] | 2 [0-4] d | 1d {2} | d {1, 2 }).) {3} (25 [0-5] | 2 [0-4] d | 1d {2} | d {1, 2}) $/

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7. Write a regular expression to match the image address in the mark of an HTML file.

/ "'s] *)/I pair

8. Regular expressions matching HTML tags

/<(. *)>. * </1> | <(. *)/>/

9. Match the Chinese phone number

(D {3}-| d {4 }-)? (D {8} | d {7 })?

10. Chinese, English, numbers, and underscores

/^ [U4e00-u9fa5_a-zA-Z0-9] + $/Dizzy does not seem to support Chinese

English, numbers, and underlines/^ [_ a-zA-Z0-9] + $/

11./^ [A-Za-z] + $ // A string consisting of 26 letters

"^ D + $" // non-negative integer (positive integer + 0)
"^ [0-9] * [1-9] [0-9] * $" // positive integer
"^ (-D +) | (0 +) $" // non-positive integer (negative integer + 0)
"^-[0-9] * [1-9] [0-9] * $" // negative integer
"^ -? D + $ "// integer
"^ D + (. d + )? $ "// Non-negative floating point number (positive floating point number + 0)
"^ ([0-9] +. [0-9] * [1-9] [0-9] *) | ([0-9] * [1-9] [0-9] *. [0-9] +) | ([0-9] * [1-9] [0-9] *) $ "// positive floating point number
"^ (-D + (. d + )?) | (0 + (. 0 + )?)) $ "// Non-positive floating point number (negative floating point number + 0)
"^ (-([0-9] +. [0-9] * [1-9] [0-9] *) | ([0-9] * [1-9] [0-9] *. [0-9] +) | ([0-9] * [1-9] [0-9] *) $ "// negative floating point number
"^ (-? D +) (. d + )? $ "// Floating point number
"^ [A-Za-z] + $" // A string consisting of 26 English letters
"^ [A-Z] + $" // a string consisting of 26 uppercase letters
"^ [A-z] + $" // a string consisting of 26 lowercase letters
"^ [A-Za-z0-9] + $" // string consisting of digits and 26 letters
"^ W + $" // a string consisting of digits, 26 letters, or underscores
"^ [W-] + (. [w-] +) * @ [w-] + (. [w-] +) + $" // email address
"^ [A-zA-z] +: // (w + (-w +) *) (. (w + (-w + )*))*(? S *)? $ "// Url
/^ (D {2} | d {4})-(0 ([1-9] {1}) | (1 [1 | 2]) -([0-2] ([1-9] {1}) | (3 [0 | 1]) $ // year-month-day
/^ (0 ([1-9] {1}) | (1 [1 | 2]) /([0-2] ([1-9] {1}) | (3 [0 | 1]) /(d {2} | d {4}) $ // month/day/year
"^ ([W-.] +) @ ([0-9] {1, 3 }. [0-9] {1, 3 }. [0-9] {1, 3 }.) | ([w-] + .) +) ([a-zA-Z] {2, 4} | [0-9] {1, 3}) (]?) $ "// Emil
/^ (+? [0-9] {2, 4}-[0-9] {3, 4}-) | ([0-9] {3, 4 }-))? ([0-9] {7,8}) (-[0-9] + )? $ // Phone number
"^ (D {1, 2} | 1dd | 2 [0-4] d | 25 [0-5]). (d {1, 2} | 1dd | 2 [0-4] d | 25 [0-5]). (d {1, 2} | 1dd | 2 [0-4] d | 25 [0-5]). (d {1, 2} | 1dd | 2 [0-4] d | 25 [0-5]) $ "// IP address
Regular Expression Matching Chinese characters: [1-?]
Match double byte characters (including Chinese characters): [^ x00-xff]
Regular expression for matching empty rows: n [s |] * r
Regular expressions matching HTML tags:/<(. *)>. * </1> | <(. *)/>/
Regular expression matching the first and last Spaces: (^ s *) | (s * $)
Regular Expression Matching the Email address: w + ([-+.] w +) * @ w + ([-.] w + )*. w + ([-.] w + )*
Regular Expression Matching URL: ^ [a-zA-z] +: // (\ w + (-\ w + )*)(\. (\ w + (-\ w + )*))*(\? \ S *)? $
Match account validity (starting with a letter, may be 5-16 bytes, may be an alphanumeric underline): ^ [a-zA-Z] [a-zA-Z0-9 _] {} $
Match Chinese phone number: (d {3}-| d {4 }-)? (D {8} | d {7 })?
Match Tencent QQ number: ^ [1-9] * [1-9] [0-9] * $
Metacharacters and their behavior in the context of regular expressions:
Mark the next character as a special character, a literal character, a back reference, or an octal escape character.
^ Matches the start position of the input string. If the Multiline attribute of the RegExp object is set, ^ matches the position after 'N' or 'R.
$ Matches the end position of the input string. If the Multiline attribute of the RegExp object is set, $ also matches the location before 'n' or 'R.
* Matches the previous subexpression zero or multiple times.
+ Match the previous subexpression once or multiple times. + Is equivalent to {1 ,}.
? Match the previous subexpression zero or one time .? It is equivalent to {0, 1 }.
{N} n is a non-negative integer that matches the specified n times.
{N ,}n is a non-negative integer and matches at least n times.
Both {n, m} m and n are non-negative integers, where n <= m. Match at least n times and at most m times. There must be no space between a comma and two numbers.
? When this character is followed by any other delimiter (*, + ,?, The matching mode after {n}, {n ,}, {n, m}) is not greedy. The non-greedy mode matches as few searched strings as possible, while the default greedy mode matches as many searched strings as possible.
. Match any single character except "n. To match any character including 'n', use a pattern like '[. n.
(Pattern) matches pattern and obtains this match.
(? : Pattern) matches pattern but does not get the matching result. That is to say, this is a non-get match and is not stored for future use.
(? = Pattern) forward pre-query: matches the search string at the beginning of any string that matches pattern. This is a non-get match, that is, the match does not need to be obtained for future use.
(?! Pattern) negative pre-query, and (? = Pattern).
X | y matches x or y.
[Xyz] character set combination.
[^ Xyz] combination of negative character sets.
[A-z] character range, matching any character in the specified range.
[^ A-z] the negative character range matches any character that is not within the specified range.
B matches a word boundary, that is, the position between a word and a space.
B matches non-word boundaries.
Cx matches the control characters specified by x.
D matches a numeric character. It is equivalent to [0-9].
D. Match a non-numeric character. It is equivalent to [^ 0-9].
F matches a form feed. It is equivalent to x0c and cL.
N matches a linefeed. It is equivalent to x0a and cJ.
R matches a carriage return. It is equivalent to x0d and cM.
S matches any blank characters, including spaces, tabs, and page breaks. It is equivalent to [fnrtv].
S matches any non-blank characters. It is equivalent to [^ fnrtv].
T matches a tab. It is equivalent to x09 and cI.
V matches a vertical tab. It is equivalent to x0b and cK.
W matches any word characters that contain underscores. It is equivalent to '[A-Za-z0-9 _]'.
W matches any non-word characters. It is equivalent to '[^ A-Za-z0-9 _]'.
Xn matches n, where n is the hexadecimal escape value. The hexadecimal escape value must be determined by the length of two numbers.
Num matches num, where num is a positive integer. References to the obtained matching.
N identifies an octal escape value or a backward reference. If n contains at least n obtained subexpressions, n is a back reference. Otherwise, if n is an octal digit (0-7), n is an octal escape value.
Nm identifies an octal escape value or a backward reference. If there are at least is preceded by at least nm obtained subexpressions before nm, then nm is backward reference. If at least n records are obtained before nm, n is a backward reference followed by m. If none of the preceding conditions are met, if n and m are octal numbers (0-7), nm matches the octal escape value nm.
If n is an octal digit (0-3) and m and l are octal numerals (0-7), nml matches the octal escape value nml.
Un matches n, where n is a Unicode character represented by four hexadecimal numbers.
Regular Expression Matching Chinese characters: [1-?]
Match double byte characters (including Chinese characters): [^ x00-xff]
Regular expression for matching empty rows: n [s |] * r
Regular expressions matching HTML tags:/<(. *)>. * </1> | <(. *)/>/
Regular expression matching the first and last Spaces: (^ s *) | (s * $)
Regular Expression Matching the Email address: w + ([-+.] w +) * @ w + ([-.] w + )*. w + ([-.] w + )*
The regular expression matching the URL: http: // ([w-] +.) + [w-] + (/[w -./? % & =] *)?
Use regular expressions to restrict text box input in a webpage form:
Use a regular expression to restrict Chinese characters only: onkeyup = "val = val. replace (/[^ 1-?] /G, '')" onbeforepaste = "clipboardData. setData ('text', clipboardData. getData ('text'). replace (/[^ 1-?] /G ,''))"
Use a regular expression to limit that only the full-width characters can be entered: onkeyup = "val = val. replace (/[^? -?] /G, '')" onbeforepaste = "clipboardData. setData ('text', clipboardData. getData ('text'). replace (/[^? -?] /G ,''))"
Use a regular expression to limit that only numbers can be entered: onkeyup = "val = val. replace (/[^ d]/g, '')" onbeforepaste = "clipboardData. setData ('text', clipboardData. getData ('text '). replace (/[^ d]/g ,''))"
Only numbers and English characters can be entered with a regular expression: onkeyup = "val = val. replace (/[W]/g, '')" onbeforepaste = "clipboardData. setData ('text', clipboardData. getData ('text '). replace (/[^ d]/g ,''))"