如何在LINQ中执行String.Replace? [英] How to do a String.Replace in LINQ?

问题描述

这是我正在尝试做的但没有成功的事情.我想呼叫from x in list1和join y in list2 where regex.Match(x.Value).Success.完成这些步骤后，我需要在x.Value上两次调用String.Replace.然后调用on和select运算符.我希望它看起来像第二个示例.如何做到这一点?

Here is what I am trying to do but with no success. I want to call from x in list1 and join y in list2 where regex.Match(x.Value).Success. After these steps I need to call String.Replace twice on x.Value. Then call the on and select operators. I want it to look something like the second example. How can this be acheived?

这是我的列表的样子:

list1              list2
Name    Value      Name    Value
item.1  $(prod1)   prod1   prodVal1
item.2  $(prod2)   prod2   prodVal2
item.3  prod3      prod3   prodVal3

这是我的列表的样子:

updatedList         
Name    Value     
item.1  prodVal1   
item.2  prodVal2       
item.3  prod3      

示例1(这是我目前拥有的):

Example 1 (This is what I currently have):

foreach (var x in list1)
{
    Match match = reg.Match(x.Value);
    if (match.Success)
    {
        x.Value = x.Value.Replace("$(", "");
        x.Value = x.Value.Replace(")", "");
    }
}

var commonItems = from x in list1
                  join y in list2
                  on x.Value equals y.Name
                  //where regex.Match(x.Value).Success
                  select new { Item = x, NewValue = y.Value };

foreach (var x in commonItems)
{
    x.Item.Value = x.NewValue;
}

示例2:

var commonItems = from x in list1
                  join y in list2
                  where regex.Match(x.Value).Success
                  //do x.Value.Replace("$(", "")
                  //do x.Value.Replace(")", "")
                  //then call
                  on x.Value equals y.Name
                  select new { Item = x, NewValue = y.Value };

foreach (var x in commonItems)
{
    x.Item.Value = x.NewValue;
}

推荐答案

您确定需要Regex.Match吗?您可以不使用它而获得相同的结果，反正我添加了两个版本...

Are you sure you need Regex.Match? you could obtain the same result without using it, anyway I added both versions...

在1°版本中，您可以使用简单的If语句来检查值是否已更改

In the 1° version you can use a simple If statement to check if the value was changed

NewValue = x.Value != x1 ? y.Value: x.Value 

示例代码

给了这堂课

class MyClass
{
    public string Name { get; set; }
    public string Value { get; set; }
}

.

添加项目

        var list1 = new List<MyClass>();
        list1.Add(new MyClass { Name = "item.1", Value = "$(prod1)" } );
        list1.Add(new MyClass { Name = "item.2", Value = "$(prod2)" });
        list1.Add(new MyClass { Name = "item.3", Value = "prod3" });

        var list2 = new List<MyClass>();
        list2.Add(new MyClass { Name = "prod1", Value = "prodVal1" });
        list2.Add(new MyClass { Name = "prod2", Value = "prodVal2" });
        list2.Add(new MyClass { Name = "prod3", Value = "prodVal3" });

获取常用列表

        var q =  from x in list1
                 let x1 = x.Value.Replace("$(", "").Replace(")", "")
                join y in list2 on x1 equals y.Name
                select new { 
                    Item = x.Name, 
                    NewValue = x.Value != x1 ? y.Value: x.Value 
                };


        foreach (var s in q)
        {
            Console.WriteLine(s.Item + " " + s.NewValue);
        }

结果

item.1 prodVal1
item.2 prodVal2
item.3 prod3

---

PS :我认为您不需要Regex，但以防万一该版本可以使用它.

---

PS: I don't think you need Regex, but just in case this version will work using it.

var q = from x in list1
        let x1 = x.Value.Replace("$(", "").Replace(")", "")
        join y in list2 on x1 equals y.Name
        select new
        {
            Item = x.Name,
            NewValue = Regex.Match(x.Value, x1).Success ? x.Value : y.Value
        };

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