如何从列表中的项目创建逗号分隔的字符串 [英] How create a comma-separated string from items in a list

问题描述

如果我在列表中打印值，则如下所示:

If I print values in a list, it will be like below:

main(List<String> arguments) {
  List cities = ['NY', 'LA', 'Tokyo'];
  String s = '';
  for(var city in cities)
    s += '$city, ';
  print(s);//NY, LA, Tokyo, 
}

但是我想用逗号分隔列表中的每个元素(不包含最后一个元素).

But I want to separate each element in a list by comma(without for the last element).

在Java中，我们可以像下面这样:

In Java we can do it like below:

List<String> cities = Arrays.asList("NY", "LA", "Tokyo");
System.out.println(cities.stream().collect(joining(", ")));//NY, LA, Tokyo

在Dart中，我完成了，如下所示:

In Dart I did it like below:

main(List<String> arguments) {
  List cities = ['NY', 'LA', 'Tokyo'];
  print(formatString(cities));//NY, LA, Tokyo
}

String formatString(List x) {
  String formatted ='';
   for(var i in x) {
     formatted += '$i, ';
   }
  return formatted.replaceRange(formatted.length -2, formatted.length, '');
}

Dart中有没有更简单的方法?

推荐答案

这就是我使用 join() /List-class.html"rel =" noreferrer> 列表 :

This is how I do it using join() in List:

main(List<String> arguments) {
  List cities = ['NY', 'LA', 'Tokyo'];

  String s = cities.join(', ');
  print(s);
}

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