Convert comma separated string of ints to int array

Question

I only found a way to do it the opposite way round  create a comma separated string from an int list or array  but not on how to convert input like string str    1 2 3 4 5   to an array or list of ints   Here is my implementation  inspired by this post by Eric Lippert        public static IEnumerable lt int gt  StringToIntList string str                if  String IsNullOrEmpty str                         yield break                     var chunks   str Split      AsEnumerable             using  var rator   chunks GetEnumerator                          while  rator MoveNext                                  int i   0                   if  Int32 TryParse rator Current  out i                                         yield return i                                    else                                       continue                                                    Do you think this is a good approach or is there a more easy  maybe even built in way   EDIT  Sorry for any confusion  but the method needs to handle invalid input like  1 2   3  or       5   etc  by skipping it

User · Answer

If you don t want to have the current error handling behaviour  it s really easy   return text Split      Select x   gt  int Parse x      Otherwise  I d use an extra helper method  as seen this morning     public static int  TryParseInt32 string text        int value      return int TryParse text  out value    value    int   null      and   return text Split      Select lt string  int  gt  TryParseInt32                         Where x   gt  x HasValue                         Select x   gt  x Value     or if you don t want to use the method group conversion   return text Split      Select t   gt  t TryParseInt32 t                         Where x   gt  x HasValue                         Select x   gt  x Value     or in query expression form   return from t in text Split             select TryParseInt32 t  into x        where x HasValue        select x Value

User · Answer

I don t see why taking out the enumerator explicitly offers you any advantage over using a foreach   There s also no need to call AsEnumerable on chunks

User · Answer

Without using a lambda function and for valid inputs only  I think it s clearer to do this   Array ConvertAll lt string  int gt  value Split       Convert ToInt32

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I think is good enough  It s clear  it lazy so it will be fast  except maybe the first case when you split the string

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This has been asked before    Net has a built-in ConvertAll function for converting between an array of one type to an array of another type   You can combine this with Split to separate the string to an array of strings  Example function    static int   ToIntArray this string value  char separator          return Array ConvertAll value Split separator   s  gt int Parse s         Taken from here

User · Answer

I have found a simple solution which worked for me   String Join     str Split

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import java util    import java io    public class problem   public static void main String args   enter code here     String line    String   lineVector    int n m i j    Scanner sc   new Scanner System in     line   sc nextLine      lineVector   line split           enter the size of the array   n Integer parseInt lineVector 0      m Integer parseInt lineVector 1      int arr      new int n  m       enter the array here   System out println  Enter the array       for i 0 i lt n i          line   sc nextLine      lineVector   line split         for j 0 j lt m j          arr i  j    Integer parseInt lineVector j              sc close          On the first line enter the size of the array separated by a comma  Then enter the values in the array separated by a comma The result is stored in the array arr   e g  input  2 3 1 2 3 2 4 6 will store values as arr     1 2 3   2 4 6

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--EDIT-- It looks like I took his question heading too literally - he was asking for an array of ints rather than a List --EDIT ENDS--  Yet another helper method     private static int   StringToIntArray string myNumbers        List lt int gt  myIntegers   new List lt int gt         Array ForEach myNumbers Split     ToCharArray     s   gt                int currentInt          if  Int32 TryParse s  out currentInt               myIntegers Add currentInt               return myIntegers ToArray        quick test code for it  too     static void Main string   args        string myNumbers    1 2 3 4 5       int   myArray   StringToIntArray myNumbers       Console WriteLine myArray Sum   ToString        sum is 15       myNumbers    1 2 3 4 5 6 bad       myArray   StringToIntArray myNumbers       Console WriteLine myArray Sum   ToString        sum is 21      Console ReadLine

User · Answer

This is for longs  but you can modify it easily to work with ints   private static long   ConvertStringArrayToLongArray string str        return str Split     ToCharArray    Select x   gt  long Parse x ToString     ToArray

User · Answer

Let us assume that you will be reading the string from the console  Import System Linq and try this one   int   input   Console ReadLine                Split      StringSplitOptions RemoveEmptyEntries               Select int Parse               ToArray

User · Answer

You should use a foreach loop  like this   public static IEnumerable lt int gt  StringToIntList string str        if  String IsNullOrEmpty str           yield break       foreach var s in str Split                 int num          if  int TryParse s  out num               yield return num            Note that like your original post  this will ignore numbers that couldn t be parsed   If you want to throw an exception if a number couldn t be parsed  you can do it much more simply using LINQ   return  str        Split      Select lt string  int gt  int Parse

[c#] Convert comma separated string of ints to int array

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