int array to string

Question

In C   I have an array of ints  containing digits only  I want to convert this array to string   Array example    int   arr    0 1 2 3 0 1     How can I convert this to a string formatted as   012301

User · Answer

You can simply use String Join function  and as separator use string Empty because it uses StringBuilder internally   string result   string Join string Empty  new    0 1 2 3 0 1      E g   If you use semicolon as separator  the result would be 0 1 2 3 0 1   It actually works with null separator  and second parameter can be enumerable of any objects  like   string result   string Join null  new object   0 1 2 3 0  A  DateTime Now

User · Answer

You can do    int   arr    0 1 2 3 0 1    string results   string Join    arr Select i   gt  i ToString    ToArray       That gives you your results

User · Answer

at net 3 5 use    String Join     new List lt int gt  array  ConvertAll i   gt  i ToString    ToArray       at net 4 0 or above use   see  Jan Remunda s answer    string result   string Join     array

User · Answer

To avoid the creation of an extra array you could do the following   var builder   new StringBuilder    Array ForEach arr  x   gt  builder Append x    var res   builder ToString

User · Answer

string Join      from i in arr select i ToString    ToArray      In the  NET 4 0 the string Join can use an IEnumerable lt string gt  directly   string Join     from i in arr select i ToString

User · Answer

The most efficient way is not to convert each int into a string  but rather create one string out of an array of chars  Then the garbage collector only has one new temp object to worry about   int   arr    0 1 2 3 0 1   string result   new string Array ConvertAll lt int char gt  arr  x   gt  Convert ToChar x    0

User · Answer

If this is long array you could use  var sb   arr Aggregate new StringBuilder      s  i     gt  s Append  i    s ToString

User · Answer

string result   arr Aggregate      s  i    gt  s   i ToString        Disclaimer  If you have a lot of digits  hundreds  at least  and you care about performance  I suggest eschewing this method and using a StringBuilder  as in JaredPar s answer

User · Answer

I realize my opinion is probably not the popular one  but I guess I have a hard time jumping on the Linq-y band wagon   It s nifty   It s condensed   I get that and I m not opposed to using it where it s appropriate   Maybe it s just me  but I feel like people have stopped thinking about creating utility functions to accomplish what they want and instead prefer to litter their code with  sometimes  excessively long lines of Linq code for the sake of creating a dense 1-liner   I m not saying that any of the Linq answers that people have provided here are bad  but I guess I feel like there is the potential that these single lines of code can start to grow longer and more obscure as you need to handle various situations   What if your array is null   What if you want a delimited string instead of just purely concatenated   What if some of the integers in your array are double-digit and you want to pad each value with leading zeros so that the string for each element is the same length as the rest   Taking one of the provided answers as an example           result   arr Aggregate string Empty   s  i    gt  s   i ToString       If I need to worry about the array being null  now it becomes this           result    arr    null    null   arr Aggregate string Empty   s  i    gt  s   i ToString       If I want a comma-delimited string  now it becomes this           result    arr    null    null   arr Skip 1  Aggregate arr 0  ToString     s  i    gt  s         i ToString       This is still not too bad  but I think it s not obvious at a glance what this line of code is doing   Of course  there s nothing stopping you from throwing this line of code into your own utility function so that you don t have that long mess mixed in with your application logic  especially if you re doing it in multiple places       public static string ToStringLinqy lt T gt  this T   array  string delimiter                   edit  let s replace this with a  better  version using a StringBuilder           return  array    null    null    array Length    0    string Empty   array Skip 1  Aggregate array 0  ToString     s  i    gt  s         i ToString             return  array    null    null    array Length    0    string Empty   array Skip 1  Aggregate new StringBuilder array 0  ToString      s  i    gt  s Append delimiter  Append i   s   gt  s ToString             But if you re going to put it into a utility function anyway  do you really need it to be condensed down into a 1-liner   In that case why not throw in a few extra lines for clarity and take advantage of a StringBuilder so that you re not doing repeated concatenation operations       public static string ToStringNonLinqy lt T gt  this T   array  string delimiter                if  array    null                           edit  replaced my previous implementation to use StringBuilder             if  array Length  gt  0                                StringBuilder builder   new StringBuilder                     builder Append array 0                    for  int i   1  i  lt  array Length  i                                          builder Append delimiter                       builder Append array i                                       return builder ToString                             else                               return string Empty                                  else                       return null                    And if you re really so concerned about performance  you could even turn it into a hybrid function that decides whether to do string Join or to use a StringBuilder depending on how many elements are in the array  this is a micro-optimization  not worth doing in my opinion and possibly more harmful than beneficial  but I m using it as an example for this problem        public static string ToString lt T gt  this T   array  string delimiter                if  array    null                           determine if the length of the array is greater than the performance threshold for using a stringbuilder                10 is just an arbitrary threshold value I ve chosen             if  array Length  lt  10                                   assumption is that for arrays of less than 10 elements                    this code would be more efficient than a StringBuilder                     Note  this is a crazy pointless micro-optimization   Don t do this                  string   values   new string array Length                    for  int i   0  i  lt  values Length  i                        values i    array i  ToString                     return string Join delimiter  values                             else                                  for arrays of length 10 or longer  use a StringBuilder                 StringBuilder sb   new StringBuilder                     sb Append array 0                    for  int i   1  i  lt  array Length  i                                          sb Append delimiter                       sb Append array i                                       return sb ToString                                    else                       return null                    For this example  the performance impact is probably not worth caring about  but the point is that if you are in a situation where you actually do need to be concerned with the performance of your operations  whatever they are  then it will most likely be easier and more readable to handle that within a utility function than using a complex Linq expression   That utility function still looks kind of clunky   Now let s ditch the hybrid stuff and do this          convert an enumeration of one type into an enumeration of another type     public static IEnumerable lt TOut gt  Convert lt TIn  TOut gt  this IEnumerable lt TIn gt  input  Func lt TIn  TOut gt  conversion                foreach  TIn value in input                        yield return conversion value                           concatenate the strings in an enumeration separated by the specified delimiter     public static string Delimit lt T gt  this IEnumerable lt T gt  input  string delimiter                IEnumerator lt T gt  enumerator   input GetEnumerator             if  enumerator MoveNext                          StringBuilder builder   new StringBuilder                    start off with the first element             builder Append enumerator Current                   append the remaining elements separated by the delimiter             while  enumerator MoveNext                                  builder Append delimiter                   builder Append enumerator Current                              return builder ToString                      else                       return string Empty                          concatenate all elements     public static string ToString lt T gt  this IEnumerable lt T gt  input                return ToString input  string Empty                 concatenate all elements separated by a delimiter     public static string ToString lt T gt  this IEnumerable lt T gt  input  string delimiter                return input Delimit delimiter                 concatenate all elements  each one left-padded to a minimum length     public static string ToString lt T gt  this IEnumerable lt T gt  input  int minLength  char paddingChar                return input Convert i   gt  i ToString   PadLeft minLength  paddingChar   Delimit string Empty           Now we have separate and fairly compact utility functions  each of which are arguable useful on their own   Ultimately  my point is not that you shouldn t use Linq  but rather just to say don t forget about the benefits of creating your own utility functions  even if they are small and perhaps only contain a single line that returns the result from a line of Linq code  If nothing else  you ll be able to keep your application code even more condensed than you could achieve with a line of Linq code  and if you are using it in multiple places  then using a utility function makes it easier to adjust your output in case you need to change it later   For this problem  I d rather just write something like this in my application code           int   arr     0  1  2  3  0  1                012301         result   arr ToString lt int gt                 comma-separated values            0 1 2 3 0 1         result   arr ToString                   left-padded to 2 digits            000102030001         result   arr ToString 2   0

User · Answer

I like using StringBuilder with Aggregate    The  trick  is that Append   returns the StringBuilder instance itself     var sb   arr Aggregate  new StringBuilder      s  i     gt  s Append  i      var result   sb ToString

User · Answer

I ve left this here for posterity but don t recommend its use as it s not terribly readable  This is especially true now that I ve come back to see if after a period of some time and have wondered what I was thinking when I wrote it  I was probably thinking  crap  must get this written before someone else posts an answer     string s   string Concat arr Cast lt object gt    ToArray

[c#] int array to string

Examples related to c#

Examples related to arrays

Examples related to string