【NT.CC】6款非常有用的JS数值格式

6款非常有用的JS数值格式

JS里面数值是如何处理的呢？因为JS不是类型那个严格的语言，因此+号也是连接号，你可以非常简单的通过+号转换为数值，但是我们也知道JS没有很多内建的处理数据格式的函数，我们必须自己来定义，下面6个就是非常经典的6个，我们需要重头开始么？当然不需要，COPY ->PASTE

当然如果你有什么创举的话，不要仅仅将其藏在硬盘上，拿出来让大家看看。

No.1 by Matt:

NO.1 使用格式传来格式化数字，这是C里面常用的形式，当然JS里面也可以了

1. /**
2. * Formats the number according to the ‘format’ string;
3. * adherses to the american number standard where a comma
4. * is inserted after every 3 digits.
5. * note: there should be only 1 contiguous number in the format,
6. * where a number consists of digits, period, and commas
7. * any other characters can be wrapped around this number, including ‘$’, ‘%’, or text
8. * examples (123456.789):
9. * ‘0′ - (123456) show only digits, no precision不显示小数部分
10. * ‘0.00′ - (123456.78) show only digits, 2 precision两位小数
11. * ‘0.0000′ - (123456.7890) show only digits, 4 precision
12. * ‘0,000′ - (123,456) show comma and digits, no precision
13. * ‘0,000.00′ - (123,456.78) show comma and digits, 2 precision分号分隔
14. * ‘0,0.00′ - (123,456.78) shortcut method, show comma and digits, 2 precision
15. *
16. * @method format
17. * @param format {string} the way you would like to format this text
18. * @return {string} the formatted number
19. * @public
20. */
22. Number.prototype.format = function(format){
23. if(! isType(format, ’string’)) {return ”;} // sanity check
25. varhasComma = -1 < format.indexOf(’,'),
26. psplit = format.stripNonNumeric().split(’.'),
27. that = this;
29. // compute precision
30. if(1 < psplit.length) {
31. // fix number precision
32. that = that.toFixed(psplit[1].length);
33. }
34. // error: too many periods
35. elseif (2 < psplit.length) {
36. throw(’NumberFormatException: invalidformat, formats should have no more than 1 period: ‘ + format);
37. }
38. // remove precision
39. else{
40. that = that.toFixed(0);
41. }
43. // get the string now that precision is correct
44. varfnum = that.toString();
46. // format has comma, then compute commas
47. if(hasComma) {
48. // remove precision for computation
49. psplit = fnum.split(’.');
51. var cnum = psplit[0],
52. parr = [],
53. j = cnum.length,
54. m = Math.floor(j / 3),
55. n = cnum.length % 3 || 3; // n cannot be ZERO or causes infinite loop
57. // break the number into chunks of 3 digits; first chunk may be less than 3
58. for (var i = 0; i < j; i += n) {
59. if (i != 0) {n = 3;}
60. parr[parr.length] = cnum.substr(i, n);
61. m -= 1;
62. }
64. // put chunks back together, separated by comma
65. fnum = parr.join(’,');
67. // add the precision back in
68. if(psplit[1]) {fnum += ‘.’ + psplit[1];}
69. }
71. // replace the number portion of the format with fnum
72. returnformat.replace(/[\d,?\.?]+/, fnum);
73. };

我们也可以注意到在荷兰或者一些国家逗号，和.号是反过来用的，如 (e.g. 1.234,56 而不是 1,234.45)但是我想转换起来也不麻烦

No.2 by Mredkj (Add commas)

NO.2高级的正则表达式实现版

1. function addCommas(nStr)
2. {
3. nStr += '';
4. x = nStr.split('.');
5. x1 = x[0];
6. x2 = x.length > 1 ? '.' + x[1] : '';
7. varrgx = /(\d+)(\d{3})/;
8. while(rgx.test(x1)) {
9. x1 = x1.replace(rgx, '$1' + ',' + '$2');
10. }
11. returnx1 + x2;
12. }

No.3 by netlobo(Strip Non-Numeric Characters From a String)

NO.3将非数值字符从字符串中剥离【正则表达式实现】

这个函数将字符串中的所有非数值字符从中玻璃，从而只剩下数值部分，该实现考虑了-号和.点，这两个符号不会被剥离，除非-号出现在中间，而.号超过一个

1. // This function removes non-numeric characters
2. functionstripNonNumeric( str )
3. {
4. str += '';
5. varrgx = /^\d|\.|-$/;
6. varout = '';
7. for(var i = 0; i < str.length; i++ )
8. {
9. if(rgx.test( str.charAt(i) ) ){
10. if( !(( str.charAt(i) == '.' && out.indexOf( '.' ) != -1 ) ||
11. (str.charAt(i) == '-' && out.length != 0 ) ) ){
12. out += str.charAt(i);
13. }
14. }
15. }
16. returnout;
17. }

No.4 by Stephen Chapman

NO.4通脱这个函数我们可以通过其8个参数任意的选择数值的不同格式化形式

1. // number formatting function
2. // copyright Stephen Chapman 24th March 2006, 10th February 2007
3. // permission to use this function is granted provided
4. // that this copyright notice is retained intact
5. functionformatNumber(num,dec,thou,pnt,curr1,curr2,n1,n2)
6. {
7. varx = Math.round(num * Math.pow(10,dec));
8. if(x >= 0) n1=n2='';
10. vary = (''+Math.abs(x)).split('');
11. varz = y.length - dec;
13. if(z<0) z--;
15. for(vari = z; i < 0; i++)
16. y.unshift('0');
18. y.splice(z, 0, pnt);
19. if(y[0] == pnt)y.unshift('0');
21. while(z > 3)
22. {
23. z-=3;
24. y.splice(z,0,thou);
25. }
27. varr = curr1+n1+y.join('')+n2+curr2;
28. returnr;
29. }

No.5 by java-scripts

NO.5这个函数通过一些确定的十进制格式将传入的数值格式化，注意小数值并不会被圆整

1. function format_number(pnumber,decimals){
2. if(isNaN(pnumber)) { return 0};
3. if(pnumber=='') { return 0};
4. varsnum = new String(pnumber);
5. varsec = snum.split('.');
6. varwhole = parseFloat(sec[0]);
7. varresult = '';
8. if(sec.length > 1){
9. vardec = new String(sec[1]);
10. dec = String(parseFloat(sec[1])/Math.pow(10,(dec.length - decimals)));
11. dec = String(whole + Math.round(parseFloat(dec))/Math.pow(10,decimals));
12. vardot = dec.indexOf('.');
13. if(dot == -1){
14. dec += '.';
15. dot = dec.indexOf('.');
16. }
17. while(dec.length <= dot + decimals){ dec += '0'; }
18. result = dec;
19. }else{
20. vardot;
21. vardec = new String(whole);
22. dec += '.';
23. dot = dec.indexOf('.');
24. while(dec.length <= dot + decimals){ dec += '0'; }
25. result = dec;
26. }
27. returnresult;
28. }

No.6 by geocities

1. function formatNumber (obj, decimal) {
2. //decimal - the number of decimals after the digit from 0 to 3
3. //-- Returns the passed number as a string in the xxx,xxx.xx format.
4. anynum=eval(obj.value);
5. divider =10;
6. switch(decimal){
7. case0:
8. divider =1;
9. break;
10. case1:
11. divider =10;
12. break;
13. case2:
14. divider =100;
15. break;
16. default: //for 3 decimal places
17. divider =1000;
18. }
20. workNum=Math.abs((Math.round(anynum*divider)/divider));
22. workStr=""+workNum
24. if (workStr.indexOf(".")==-1){workStr+="."}
26. dStr=workStr.substr(0,workStr.indexOf("."));dNum=dStr-0
27. pStr=workStr.substr(workStr.indexOf("."))
29. while (pStr.length-1< decimal){pStr+="0"}
31. if(pStr =='.') pStr ='';
33. //--- Adds a comma in the thousands place.
34. if (dNum>=1000) {
35. dLen=dStr.length
36. dStr=parseInt(""+(dNum/1000))+","+dStr.substring(dLen-3,dLen)
37. }
39. //-- Adds a comma in the millions place.
40. if(dNum>=1000000) {
41. dLen=dStr.length
42. dStr=parseInt(""+(dNum/1000000))+","+dStr.substring(dLen-7,dLen)
43. }
44. retval = dStr + pStr
45. //-- Put numbers in parentheses if negative.
46. if (anynum<0) {retval="("+retval+")";}
48. //You could include a dollar sign in the return value.
49. //retval = "$"+retval
50. obj.value = retval;
51. }

---

How number is treated in JavaScript? JavaScript is loosely typed and the plus operator also concatenates, you can easily convert JavaScript Numbers to Strings similar to this: 1 + “”, but as we all know that JavaScript doesn’t have many built-in methods to format numbers. Most of the time we need to write our customized code to do it.The following is 6 very useful JavaScript number format function,why have to re-inventing the wheel? Don’t waste your valuable time to write it by yourself, only copy which you like and use it!

Of course if you had wrote your proudly number format function,don’t only stock in your hard disk( or your head), let’s share!

No.1 by Matt:

Basically, you can pass in a String as the format that contain any one number,and the result will replace the number in the format String with the properly formatted Number object. See the comment block for details.

1. /**
2. * Formats the number according to the ‘format’ string;
3. * adherses to the american number standard where a comma
4. * is inserted after every 3 digits.
5. * note: there should be only 1 contiguous number in the format,
6. * where a number consists of digits, period, and commas
7. * any other characters can be wrapped around this number, including ‘$’, ‘%’, or text
8. * examples (123456.789):
9. * ‘0′ - (123456) show only digits, no precision
10. * ‘0.00′ - (123456.78) show only digits, 2 precision
11. * ‘0.0000′ - (123456.7890) show only digits, 4 precision
12. * ‘0,000′ - (123,456) show comma and digits, no precision
13. * ‘0,000.00′ - (123,456.78) show comma and digits, 2 precision
14. * ‘0,0.00′ - (123,456.78) shortcut method, show comma and digits, 2 precision
15. *
16. * @method format
17. * @param format {string} the way you would like to format this text
18. * @return {string} the formatted number
19. * @public
20. */
22. Number.prototype.format = function(format){
23. if(! isType(format, ’string’)) {return ”;} // sanity check
25. varhasComma = -1 < format.indexOf(’,'),
26. psplit = format.stripNonNumeric().split(’.'),
27. that = this;
29. // compute precision
30. if(1 < psplit.length) {
31. // fix number precision
32. that = that.toFixed(psplit[1].length);
33. }
34. // error: too many periods
35. elseif (2 < psplit.length) {
36. throw(’NumberFormatException: invalidformat, formats should have no more than 1 period: ‘ + format);
37. }
38. // remove precision
39. else{
40. that = that.toFixed(0);
41. }
43. color: rgb(
    分享到：
    使用WHERE语句对SQL进行基础性的优化 | 【转自 技术.人生】[ajax]FireFox和IE下 ...
    • 2008-04-26 22:24
    • 浏览 944
    • 评论(0)
    • 查看更多