Question

我有两个列表，其中包含不同数量的项目。

(function() {
    'use strict';
    /**
    * @ngdoc service
    * @name gemStoreApp.productService
    * @description
    * # productService
    */
    angular.module('gemStoreApp.productService',['ngResource'])
        .factory('productsService', function($resource) {
            return $resource('/products/:id', {id:'@id'},{
                'update': { method: 'PUT'}
            });
        });
    })();

现在我想从这些列表中得到最终结果。

__init__.py

如果列表被反转，如

a = {"a","b","c","d","e"}<br>
b = {"f","g","h"}

结果将是

a,f
b,g
c,h
d
e

我试图在互联网上搜索，但我的搜索总是会出现这种情况。

a = {"f","g","h"}
b = {"a","b","c","d","e"}

显示错误的结果

f,a
g,b
h,c
,d
,e

Answer 1

我的更多选择

var c = Enumerable.Range(0, Math.Max(a.Length, b.Length))
        .Select(i => (i < a.Length ? a[i] : "") + "," + (i < b.Length ? b[i] : ""))
        .ToList();

或

var c = a.Select((s, i) => new { s, i }) .Concat(b.Select((s, i) => new { s, i })) .GroupBy(x => x.i) .Select(g => string.Join(",", g.Select(x => x.s))) .ToList();

查看输出：

Console.WriteLine(String.Join(Environment.NewLine, c));

Answer 2

对于两个列表的配对元素，您可以使用Enumerable.Zip：

var a = new [] { "a", "b", "c", "d", "e"};
var b = new [] { "f", "g", "h" };
var c = a.Zip(b, (x, y) => x + "," + y);

您可以使用一些额外的逻辑来处理尾随元素：

if (a.Length > b.Length)
    c = c.Concat(a.Skip(b.Length));
else if (b.Length > a.Length)
    c = c.Concat(b.Skip(a.Length).Select(y => "," + y));

foreach (string z in c)
    Console.WriteLine(z);

Answer 3

这样的事情：

var a = new string[]{"a","b","c","d","e"};
var b = new string[]{"f","g","h"};

var l = Math.Max(a.Length, b.Length);
a = a.Concat(Enumerable.Repeat((string)null, l - a.Length)).ToArray();
b = b.Concat(Enumerable.Repeat((string)null, l - b.Length)).ToArray();

var c = a.Zip(b, (x,y) => x == null ? y : y == null ? x : x + "," + y);

首先使用空值填充两个数组，使它们的长度相同，然后将它们Zip放在一起。结果：

a,f
b,g
c,h
d
e

在VB.Net中，它会像一样（无法弄清楚如何翻译VB中的(string)null部分）：

dim a = {"a","b","c","d","e"}
dim b = {"f","g","h"}

dim l = Math.Max(a.Length, b.Length)

a = a.Concat(Enumerable.Repeat("", l - a.Length)).ToArray()
b = b.Concat(Enumerable.Repeat("", l - b.Length)).ToArray()

dim c = a.Zip(b, Function(x,y) if (x = "", y, if (y = "", x , x + "," + y)))

LINQ Concate Two List制作一个csv列表

3 个答案: