How PHP determines whether it is a number or a character type

This article describes how to determine whether a number, or a character type, is a method in PHP programming. Refer to a friend who needs it. First, PHP is verifying that the string is a number. Method one: In PHP with regular validation is a number, very simple, master the basic regular expression can be. For example: Method Two: The key parameters must be filtered. For example, the number regular filter: The difference between the two methods: The Is_numeric decimal is also considered a number, whereas the preceding one treats the decimal point as a character. Common regular operations: Verify Number: ^[0-9]*$ Verify N-bit number: ^\d{n}$ validates at least n digits: ^\d{n,}$ verifies the number of m-n bits: ^\d{m,n}$ verify 0 and non 0 numbers starting with: ^ (0|[ 1-9][0-9]*) $ verifies that there is a positive real number with two decimal places: ^[0-9]+ (. [ 0-9]{2})? $ Verify that there is a positive real number with 1-3 decimal places: ^[0-9]+ (. [ 0-9]{1,3})? $ verify non-zero positive integers: ^\+? [1-9] [0-9]*$ validates a nonzero negative integer: ^\-[1-9][0-9]*$ validates a non-negative integer (positive integer + 0) ^\d+$ validates a non-positive integer (negative integer + 0) ^ ((-\d+) | ( 0+) $ to verify the character length 3: ^. {3}$ validates a string of 26 English letters: ^[a-za-z]+$ validates a string of 26 uppercase English letters: ^[a-z]+$ validates a string consisting of 26 lowercase English letters: ^[a-z]+$ validates a string consisting of a number and 26 English letters: ^[ a-za-z0-9]+$ validates a string consisting of numbers, 26 letters, or underscores: ^\w+$ Verify user password: ^[a-za-z]\w{5,17}$ the correct format is: Start with a letter, the length is between 6-18, and can contain only characters, numbers, and underscores. Verify that it contains ^%& ',; =?$\ "characters:[^%& ',; =?$\x22]+ Verify kanji: ^[\u4e00-\u9fa5],{0,}$ Verify email Address: ^\w+[-+.] \w+) *@\w+ ([-.] \w+) *\.\w+ ([-.] \w+) *$ authentication interneturl:^http://([\w-]+\.) +[\w-]+ (/[\w-./?%&=]*)? $; ^[a-za-z]+://(w+ (-w+) *) (. ( w+ (-w+) *) * (? s*)? $ authentication Phone number: ^ (\ (\d{3,4}\) |\d{3,4}-)? \d{7,8}$:– the correct format is: xxxx-xxxxxxx,xxxx-xxxxxxxx,xxx-xxxxxxx,xxx-xxxxxxxx, Xxxxxxx,xxxxxxxx. Verifying a Social Security number (15-bit or 18-digit number): ^\d{15}|\d{}18$ validation 12 months of the year: ^ (0?[ 1-9]|1[0-2]) $ correct format for: "01"-"09" and "1" "12" verify one-month 31 days: ^ (0?[ 1-9]) | ((1|2) [0-9]) |30|31) $ The correct format is: 01, 09 and 1, 31. Integer: ^-?\d+$ non-negative floating-point number (positive floating pointNumber + 0): ^\d+ (\.\d+)? $ positive floating point ^ ([0-9]+\.[ 0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\. [0-9]+) | ([0-9]*[1-9][0-9]*)) $ non-positive floating-point number (negative floating-point number + 0) ^ ((-\d+ (\.\d+)?) | (0+ (\.0+)?)) $ negative floating-point number ^ (-([0-9]+\.[ 0-9]*[1-9][0-9]*) | ([0-9]*[1-9][0-9]*\. [0-9]+) | ([0-9]*[1-9][0-9]*))) $ floating point ^ (-?\d+) (\.\d+)? In PHP programming, reasonable use of PHP regular, sometimes really will be more effective, the effect is not generally good.

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