在C＃中操作列表 [英] Manipulating lists in C #

问题描述

大家好，



我有一个想法，我仍然不确定如何在实践中解决。



我有一个字符串列表，这些字符串都由6位数组成。 " 012345" ;.我想要的是在列表中添加这些字符串。



现在有了这个列表，我想浏览整个列表并选择每个位置，字符串的第一个数字。最后我想形成一个包含所有数字的数组。



示例：我有一个列表{012345,032165,211458,214563,098796,574623,894235 ，3135698}



滚动列表以形成新的向量，如下所示：[0,0,2,2,0,5,8,3]是列表中每个元素的第一个值。



第一部分我想解决这个问题。

第二部分我将随机选择一个位置，主列表中的任何向量，然后执行以下操作：我想构建一个新列表，只有文件名以数字值绘制矢量开头。



示例：如果向量绘制了值0，我想构建一个只包含这些值的新列表：{012345,032165,098796}



任何想法？如果我对这个想法不是很清楚，请告诉我一些事情

解决方案

要解决第一个问题，请使用以下代码：

< pre lang =cs> List< string> yourList = new 列表< string>（）{ 012345 ， 032165， 211458， 214563， 098796， < span class =code-string> 574623， 894235， 3135698};
List< string> firstDigits = yourList.Select（x = > x.Substring（ 0 ， 1 ））。ToList（）;

关于第二个问题，我不确定，但试试这个，告诉我是否这不是你想要的：

随机r =  new  Random（）; 
  int  max = yourList.Select（x = >  x.Length）.Min（ ）; 
  int  randomNum = r.Next（ 9 ）; 
 List< string> newList = yourList.Where（x = >  x.StartsWith（randomNum.ToString（））; 

希望这会有所帮助。

第一部分很简单：

 List< string> myList =  new  List< string>（）{  012345，  032165，  211458，  214563，  098796，  574623，  894235，   3135698}; 
  char  [] chars =  NE w   char  [myList.Count]; 
  int  index =  0 ; 
  foreach （ string  s  in  myList）
 {
 chars [index ++] = s.Length >   0 ？ s [ 0 ]：' ？' ; 
} 

第二部分也非常简单 - 你所要做的就是为foreach循环添加一个列表和一个简单的条件。



但是因为这听起来像是家庭作业，我会把它留给你！

Hello guys,

I have an idea where I still not sure how to solve in practice.

I have a list of string, these strings are all formed by 6 digits. "012345". what I want is to add these strings in a list.

Now with this list made​​, I want to go through the whole list and go picking at each position, the first digit of the string. in the end I want to form an array with all digits caught.

example: I have a list {012345, 032165, 211458, 214563, 098796, 574623, 894235, 3135698}

to scroll through the list to form the new vector like this: [0, 0, 2, 2, 0, 5, 8, 3] which is the first value of each element of the list.

first part I want to solve this problem.
second part I will randomly select a position that any vector in the main list and go and do the following: I want to build or a new list with only the file name starts with digit values ​​drawn vector.

example: if the vector drawn the value "0", I want to build a new list with only those values​​: {012345, 032165, 098796}

any ideas? If I am not very clear on the idea, please tell me something

解决方案

To solve the first problem, use this code:

List<string> yourList = new List<string>() { "012345", "032165", "211458", "214563", "098796", "574623", "894235", "3135698"};
List<string> firstDigits = yourList.Select(x => x.Substring(0, 1)).ToList();

About the second problem, I'm not sure, but try this, and tell me if this isn't what you want:

Random r = new Random();
int max = yourList.Select(x => x.Length).Min();
int randomNum = r.Next(9);
List<string> newList = yourList.Where(x => x.StartsWith(randomNum.ToString());

Hope this helps.

The first part is easy:

List<string> myList = new List<string>() { "012345", "032165", "211458", "214563", "098796", "574623", "894235", "3135698" };
char[] chars = new char[myList.Count];
int index = 0;
foreach (string s in myList)
    {
    chars[index++] = s.Length > 0 ? s[0] : '?';
    }

The second part is also pretty simple - all you have to do is add a list, and a simple condition to the foreach loop.

But since this sounds like homework, I'll leave that to you!

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