应用JavaScript正则表达式实现一些实用函数
使用JavaScript正则表达式实现一些实用函数
//去除字符串空格
/*** Start of Modify ***/
function ltrim(str){
/* Trims leading spaces - returns string
* Returns trimmed string
*/
return str.replace(/^\s+/, '');
}//eof - ltrim
function rtrim(str) {
/* Trims trailing spaces - returns string
* Returns trimmed string
*/
return str.replace(/\s+$/, '');
}//eof - rtrim
function alltrim(str) {
/* Trims leading and trailing spaces
* Returns trimmed string
*/
return str.replace(/^\s+|\s+$/g, '');
}//eof - alltrim
function padleft(str, ch, num) {
/* Pads string on left with number characters
* Args:
* str = string to pad
* ch = pad character
* num = number of total characters in final string
* returns string
*/
ch = ch || " "; //otherwise pad.length remains 0.
//Create pad string num chars
var pad = "";
do {
pad += ch;
} while(pad.length < num);
//Regular express take num chars from right
var re = new RegExp(".{" + num + "}$")[0];
return re.exec(pad + str);
}//eof - padleft
function padright(str, ch, num){
/* Pads string on right with number characters
* Args:
* str = string to pad
* ch = pad character
* num = number of total characters in final string
* returns string
*/
ch = ch || " "; //otherwise pad.length remains 0.
//Create pad string num chars
var pad = "";
do {
pad += ch;
} while (pad.length < num);
//Regular express take num chars from left
var re = new RegExp("^.{" + num + "}");
return re.exec(str + pad)[0];
}//eof - padright
function padcenter(str, ch, size, extra2right) {
/* Centers string in a string by padding on right and left
* Args:
* str = string to center
* ch = pad character
* size = number of total characters in final string
* extra2right = optional true if extra character should be on right
* returns string
*/
var padStr = "";
var re;
var len = str.length;
var rtrnVal;
if (len <= size) {
if (extra2right)
re = new RegExp("^(.*)(.{" + len + "})(\\1)");
else
re = new RegExp("(.*)(.{" + len + "})(\\1)$");
do {
padStr += ch;
} while (--size);
rtrnVal = padStr.replace(re, "$1" + str +"$3");
} else {
rtrnVal = extractMiddle(str, size, extra2right);
}
return rtrnVal;
}//eof padcenter
function centerInStr(inStr, outStr, extra2right) {
/* Centers string in a string of same characters
* Args:
* inStr = string to center
* outStr = string of same character
* extra2right = optional true if extra character should be on right
* returns string
*/
var padStr = "";
var re;
var len = inStr.length;
var size = outStr.length;
var rtrnVal;
if (len <= size) {
if (extra2right)
re = new RegExp("^(.*)(.{" + len + "})(\\1)");
else
re = new RegExp("(.*)(.{" + len + "})(\\1)$");
rtrnVal = outStr.replace(re, "$1" + inStr +"$3");
} else {
rtrnVal = extractMiddle(inStr, size, extra2right);
}
return rtrnVal;
}//eof centerInStr
function centerInStr2(inStr, outStr, extra2right) {
/* Centers string in a string of mixed characters replacing characters
* Args:
* inStr = string to center within outStr
* outStr = the outer string
* extra2right = optional true if extra character should be on right
* returns string
*/
var inSize = inStr.length;
var outSize = outStr.length;
var l = Math.floor( (outSize - inSize) /2);
var re;
var rtrnVal;
if (inSize <= outSize) {
if (extra2right)
re = new RegExp("(.{"+l+"})(.{" + inSize + "})(.*)");
else
re = new RegExp("(.*)(.{" + inSize + "})(.{"+l+"})");
rtrnVal = outStr.replace(re, "$1" + inStr + "$3");
} else {
rtrnVal = extractMiddle(inStr, outSize, extra2right);
}
return rtrnVal;
}//eof centerInStr2
function centerInStr3(inStr, outStr, extra2right) {
/* Centers string in a mixed string without replacing characters
* Args:
* inStr = string to center within outStr
* outStr = the outer string
* extra2right = optional true if extra character should be on right
* returns string
*/
var outSize = outStr.length;
var inSize = inStr.length;
var l = Math.floor(outSize/2);
var re;
var rtrnVal;
if (inSize <= outSize) {
if (extra2right)
re = new RegExp("(.{" + l + "})(.*)");
else
re = new RegExp("(.*)(.{" + l + "})");
rtrnVal = outStr.replace(re, "$1" + inStr + "$2");
} else {
rtrnVal = extractMiddle(inStr, outSize, extra2right);
}
return rtrnVal;
}//eof centerStr3
function extractMiddle(str, size, extra2right) {
/* Centers string in a string by padding on right and left
* Args:
* inStr = string to center within outStr
* outStr = the outer string
* extra2right = optional true if extra character should be on right
* returns string
*/
var l = Math.floor( (str.length - size)/2);
var re;
if (extra2right)
re = new RegExp("(.{" + l + "})(.{" + size + "})(.*)");
else
re = new RegExp("(.*)(.{" + size + "})(.{" + l + "})");
return str.replace(re, "$2");
}//eof extractMiddle
function back2forward(dataStr){
return dataStr.replace(/\\/g, "/");
}
function forward2back(dataStr) {
return dataStr.replace(/\//g, "\\");
}
function return2br(dataStr) {
/* Convert returns in string to html breaks
* return string
*/
return dataStr.replace(/(\r\n|[\r\n])/g, "<br />");
}//eof - return2br
function return2br2(dataStr) {
/* Convert returns in string to html breaks
* return string
*/
return dataStr.replace(/(\r\n|\r|\n)/g, "<br />");
}//eof - return2br2
function cleanString(str) {
/* Remove specified characters from string
* Arg: str = string to clean
* List is left parenthesis, right parenthesis, period, dash, space
* Change list inside square brackets [list]
* Return string
*/
return str.replace(/[\(\)\.\-\s,]/g, "");
}//eof - cleanString
function cleanString2(str) {
return str.replace(/[^\d]/g, "");
}
function alpha2numericPhone(phoneStr) {
var newStr = phoneStr.replace(/[a-zA-Z]/g, alpha2number);
return checkReplaceParm(newStr, "alpha2number");
function alpha2number(char) {
var rtrnVal = null;
switch (char.toLowerCase()) {
case "a": case "b": case "c":
rtrnVal = "2";
break;
case "d": case "e": case "f":
rtrnVal = "3";
break;
case "g": case "h": case "i":
rtrnVal = "4";
break;
case "j": case "k": case "l":
rtrnVal = "5";
break;
case "m": case "n": case "o":
rtrnVal = "6";
break;
case "p": case "q": case "r": case "s":
rtrnVal = "7";
break;
case "t": case "u": case "v":
rtrnVal = "8";
break;
case "w": case "x": case "y": case "z":
rtrnVal = "9";
break;
}
return rtrnVal;
}
}
function first_first(name) {
return name.replace(/^([^,]*)[,\s]+(\w+)/, "$2 $1");
}
function last_first (name) {
return name.replace(/(.+)\s+([\w']+)$/, "$2, $1"); //'
}
function switchWords(name) {
/* Change order of two words removing optional comma separator
* Arg: name = string of two words
* Return string no separator
*/
return name.replace(/(\w+),?\s*(\w+)/, "$2 $1");
}//eof - switchWords
function reversOrder (name) {
/* Change order of two words inserting comma separator
* Args: name = string of two words
* Return string with separator
*/
return name.replace(/(\w+),?\s+(\w+)/, "$2, $1");
}//eof - reversOrder
function cnvrt2upper(str) {
/* Convert string to title case capital first letters
* Return converted string or original string if not supported
*/
str = alltrim(str);
var newStr = str.toLowerCase().replace(/\b[a-z]/g, cnvrt)
return checkReplaceParm(newStr, "cnvrt");
function cnvrt() {
return arguments[0].toUpperCase();
}
}//eof - cnvrt2upper
function titleCase(str) {
str = alltrim(str);
var newStr = str.toLowerCase().replace(/\b\w+\b/g, cnvrt);
return checkReplaceParm(newStr, "cnvrt");
function cnvrt() {
/*Branch which should be capitalized */
if (arguments[arguments.length -2] == 0)
/* First word capitalize if first char is letter*/
return arguments[0].replace(/^[a-z]/, cnvrt2);
else if (/^(a|about|after|an|and|at|by|for|from|in|into|nor|of|on|onto|over|the|to|up|with|within)$/.test(arguments[0]) )
/* List of words to skip */
return arguments[0];
else
/* All other capitalize if first character is letter */
return arguments[0].replace(/^[a-z]/, cnvrt2);
}
function cnvrt2() {
/* Capitalize letter */
return arguments[0].toUpperCase();
}
}//eof
function titleCase2(str) {
var re = new RegExp(/^(a|about|after|an|and|at|by|for|from|in|into|nor|of|on|onto|over|the|to|up|with|within)$/);
return str.toLowerCase().replace(/\b([a-z])(\w*)\b/g, cnvrt);
function cnvrt() {
if (re.test(arguments[0]) && arguments[arguments.length-2])
return arguments[0];
else
return arguments[1].toUpperCase() + arguments[2];
}
}
function html2entity(str) {
/* Convert html <,> to &tl; and >
* Agr: str = string that may have html
* Return converted string or original string if not supported
*/
var newStr = cnvrt(str);
return checkReplaceParm(newStr, "(s)");
function cnvrt(str){
//replace with function
return str.replace(/[<>]/g, function (s){ return (s == "<")? "<" :">"});
}
}//eof - html2entity
function checkReplaceParm(str, fx) {
/* Check browser supports functions in replace
* No support returns function itself
*/
var re = new RegExp("^\sfunction\s+" + fx);
if (re.test(str)) {
/* This return can be change to null or
* a value of your choice to indicate failure
*/
alert("This browser doesn't support using a function as an argument to the replace method!");
return ""
}
else {
return str;
}
}
/** regexp-parsing-data.js ***/
function xtractReportType1(data) {
/* Approach 1 to extracting data from a string and putting it in another string
* Arg: data = source data
* Return new string
* This fx is of no value accept as a demo.
* Watchout for dashes
*/
var array = data.match(/\b[\S]+\b/g);
return array[5] + " " + array[0] + " paint retail price: $" + array[2] + " ea.";
}//eof - xtractReportType1
function xtractReportType2(data){
/* Approach 2 to extracting data from a string and putting it in another string
* Arg: data = source data
* Return new string
* This fx is of no value accept as a demo, and not recommended option.
*/
data.match(/^(\S+)\s(\S+)\s(\S+)\s(\S+)\s(\S+)\s(\S+)\b/);
return RegExp.$6 + " " + RegExp.$1 + " paint retails for $" + RegExp.$3 + " ea.";
}//eof - xtractReportType2
function xtractNums(str){
/* Create array of numbers in string
* Arg: str = source string containing numbers
* can be mixed with words.
* Return array of numbers in str
* Unlike the previous two, you can use this
*/
return str.match(/\d+/g);
}//eof - xtractNums
function xtractFormattedNums(data) {
/* Create array of numbers in string (including formatted with commas and decimal)
* Arg: data = source string containing numbers
* can be mixed with words.
* Return array of numbers in str
*/
return data.match(/\d+(,\d{3})*(\.\d{1,2})?/g);
}//eof - xtractFormattedNums
function parseUrl(url) {
/* Parse URL into protocol, host, path, file and hash (and url)
* must be URL only
* Args: url
* Return object or null if no match
*/
url = url.replace(/^\s+|\s+$/g, ''); //alltrim
if (url.match(/^((http|ftp):\/)?\/?([^:\/\s]+)((\/\w+)*\/)([\w\-\.]+\.[^#?\s]+)(#[\w\-]+)?$/)) {
//RegExp['$&'] is null in some browsers s/b original url
return {url: RegExp['$&'], protocol: RegExp.$2,host:RegExp.$3,path:RegExp.$4,file:RegExp.$6,hash:RegExp.$7};
}
else {
return null;
}
}//eof - parseUrl
function parseEmeddedUrl(url) {
/* Parse URL into protocol, host, path, file and hash (and url)
* can be embedded in string
* Args: url
* Return object or null if no match
*/
var e = /((http|ftp):\/)?\/?([^:\/\s]+)((\/\w+)*\/)([\w\-\.]+\.[^#?\s]+)(#[\w\-]+)?/
if (url.match(e)) {
//RegExp['$&'] is null in some browsers s/b original url
return {url: RegExp['$&'], protocol: RegExp.$2,host:RegExp.$3, path:RegExp.$4,file:RegExp.$6,hash:RegExp.$7};
}
else {
return null;
}
}//eof - parseEmeddedUrl
function xtractFile(data){
/* Separate path and filename.ext
* Arg: string with path and filename
* Return: object
*/
if (data.match(/(.*)\/([^\/\\]+\.\w+)$/)) {
return {path: RegExp.$1, file: RegExp.$2};
}
else {
return {path: "", file: ""};
}
}//eof - xtractFile
function xtractFile_sans(data){
/* Separate path and filename leaving extention off
* Assumes DOS style with only one dot.
* Arg: string with path and filename
* Return: object
*/
if (data.match(/(.*)\/([^\/\\]+)\.\w+$/)) {
return {path: RegExp.$1, file: RegExp.$2};
}
else {
return {path: "", file: ""};
}
}//eof - xtractFile_sans
function xtractFile-ext1(data){
/* Parses filename and extension
*
* Returns Object
*/
data = data.replace(/^\s|\s$/g, "");
if (/\.\w+$/.test(data)) {
var m = data.match(/([^\/\\]+)\.(\w+)$/);
if (m)
return {filename: m[1], ext: m[2]};
else
return {filename: "no file name", ext:null};
} else {
var m = data.match(/([^\/\\]+)$/);
if (m)
return {filename: m[1], ext: null};
else
return {filename: "no file name", ext:null};
}
}//eof - xtractFile-ext1
function xtractFile-ext2(data){
/* Parses filename and extension
*
* Returns Object
*/
data = data.replace(/^\s|\s$/g, ""); //trims string
if (/\.\w+$/.test(data)) }
if (data.match(/([^\/\\]+)\.(\w+)$/) )
return {filename: RegExp.$1, ext: RegExp.$2};
else
return {filename: "no file name", ext:null};
}
else {
if (data.match(/([^\/\\]+)$/) )
return {filename: RegExp.$1, ext: null};
else
return {filename: "no file name", ext:null};
}
}//eof - xtractFile-ext2
function xtractFile-ext4type(data){
/* Parses filename and extension
* for specified extenstions
*
* Returns Object
*/
data = data.replace(/^\s|\s$/g, ""); //trims string
if (data.match(/([^\/\\]+)\.(asp|html|htm|shtml|php)$/i) )
return {filename: RegExp.$1, ext: RegExp.$2};
else
return {filename: "invalid file type", ext: null};
}//eof - xtractFile-ext4type
//from http://lawrence.ecorp.net/inet/samples/regexp-format.php