Dart如何将逗号添加到字符串编号 [英] Dart how to add commas to a string number

问题描述

我正在尝试对此进行调整:将逗号插入数字字符串可以飞镖工作，但是没有运气.

I'm trying to adapt this: Insert commas into number string to work in dart, but no luck.

这两个都不起作用:

print("1000200".replaceAllMapped(new RegExp(r'/(\d)(?=(\d{3})+$)'), (match m) => "${m},"));
print("1000300".replaceAll(new RegExp(r'/\d{1,3}(?=(\d{3})+(?!\d))/g'), (match m) => "$m,"));

是否有更简单/可行的方式将逗号添加到字符串编号?

Is there a simpler/working way to add commas to a string number?

推荐答案

您只是忘记了将第一位数字分组.使用这个简短的例子:

You just forgot get first digits into group. Use this short one:

'12345kWh'.replaceAllMapped(new RegExp(r'(\d{1,3})(?=(\d{3})+(?!\d))'), (Match m) => '${m[1]},')

查看可读版本.在表达式的最后一部分中，我添加了对任何非数字字符(包括字符串结尾)的检查，以便您也可以将其与"12瓦特"一起使用.

Look at the readable version. In last part of expression I added checking to any not digit char including string end so you can use it with '12 Watt' too.

RegExp reg = new RegExp(r'(\d{1,3})(?=(\d{3})+(?!\d))');
Function mathFunc = (Match match) => '${match[1]},';

List<String> tests = [
  '0',
  '10',
  '123',
  '1230',
  '12300',
  '123040',
  '12k',
  '12 ',
];

tests.forEach((String test) {
  String result = test.replaceAllMapped(reg, mathFunc);
  print('$test -> $result');
});

它完美地工作:

0 -> 0
10 -> 10
123 -> 123
1230 -> 1,230
12300 -> 12,300
123040 -> 123,040
12k -> 12k
12  -> 12 

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