Geek asks and answers

Joining a list in a different way

Language: C # 4.0

Exists List<string>with values ​​Value1, Value2, Value3, etc.
I would like to make a connection in the general list so that the output is

string values = "Value1, Value2 and Value3";

and if there is only one value

string values = "Value1";

I am currently replacing LastIndexOf ,with and. But I didn’t like it. What is the most effective way to join this?

+3
source share
7 answers

You can use the function for this String.Join(string glue, string[] array);.

string values = String.Join(", ", myList.ToArray());

Hope this helps. (Note: myListis a list that you already have in your application.)

Update: your noticed and the requirement is too late, my applications, here is a small update:

string values = String.Join(", ", myList.Take(myList.Count - 1)) 
                   + " and " + myList.Last();

(, , ) StringBuilder . (: , .)

: .

public static string SmartJoin(this List<string> items, string lastSeparator)
{
    string values = "";
    if(!items.Any())
    {
        return "";
    }
    if (items.Count > 1)
    {
        values = String.Format("{0} {1} {2}",
                    String.Join(", ", items.Take(items.Count - 1)),
                    lastSeparator,
                    items.Last());
    }
    else
    {
        values = items.First();
    }
    return values;
}


string values = myList.SmartJoin("and");
+2
StringBuilder sb = new StringBuilder();
for (int i = 0; i < list.Count; i++)
{
  if (i == sb.Count - 1)
  {
    sb.Append(" and ");
  }
  else if (i > 0)
  {
    sb.Append(", ");
  }
  sb.Append(list[i])
}
+4

Enumerable -namespace :)

List<string> values = new List<string>() { "Value1", "Value2", "Value3"};
string result = "";
if (values.Count == 1) {
    result = values[0];
}
else if (values.Count > 1 ) {
    var init = values.Take(values.Count - 1);
    var temp = init.Aggregate((acc, x) => acc + ", " + x);
    temp += " and " + values[values.Count -1];
    result = temp;
}
+3

:

var sb = new StringBuilder();
for(int i = 0; i < items.Count; i++)
{
    if(i != 0)
    {
        if(i == items.Count-1) sb.Append(" and ");
        else sb.Append(", ");
    }
    sb.Append(items[i]);
}
return sb.ToString();

, ( , " and "), - .

+2

:

 public string SmartJoin(string lastSeparator, List<string> array)
 {
   var lastElementPosition = array.Count - 1;
   var lastValue = array[lastElementPosition];
   array.RemoveAt(lastElementPosition);

   return String.Join(lastSeparator, new[] { String.Join(", ", array), lastValue });
 }

:

   var items = new List<string> { "Value1", "Value2", "Value3" };
   var result =  SmartJoin(" and ", items);
+1

:

private static string ConvertToString(List<string> list)
{
    if (!list.Any())
    {
        return string.Empty;
    }

    if (list.Count == 1)
    {
        return list.First();
    }

    return string.Join(", ", list.Take(list.Count - 1)) + " and " + list.Last();
}


var list1 = new List<string> { "Value1", "Value2", "Value3", "Value4" };
var list2 = new List<string> { "Value1", "Value2", "Value3" };
var list3 = new List<string> { "Value1", "Value2" };
var list4 = new List<string> { "Value1" };
Console.WriteLine(ConvertToString(list1));
Console.WriteLine(ConvertToString(list2));
Console.WriteLine(ConvertToString(list3));
Console.WriteLine(ConvertToString(list4));

. .net 4

UPDATE: remote unnecessary code UPDATE2: some code optimization used some tips in the form of @KilZone

+1
source 
var sb = new StringBuilder();
if (yourList.Count > 0)
{
    sb.Append(yourList[0]);

    if (yourList.Count > 1)
    {
        for (int i = 1; i < yourList.Count - 1; i++)
        {
            sb.Append(", ").Append(yourList[i]);
        }

        sb.Append(" and ").Append(yourList[yourList.Count - 1]);
    }
}
string values = sb.ToString();
+1
source

More articles:


All Articles