Is there an easy way to return a string repeated X number of times

Question

I m trying to insert a certain number of indentations before a string based on an items depth and I m wondering if there is a way to return a string repeated X times   Example   string indent    ---   Console WriteLine indent Repeat 0      would print nothing  Console WriteLine indent Repeat 1      would print  ---   Console WriteLine indent Repeat 2      would print  ------   Console WriteLine indent Repeat 3      would print  ---------

User · Answer

most performant solution for string  string result   new StringBuilder   Insert 0   ---   5  ToString

User · Answer

If you only intend to repeat the same character you can use the string constructor that accepts a char and the number of times to repeat it new String char c  int count    For example  to repeat a dash five times   string result   new String  -   5   Output  -----

User · Answer

Works with strings and chars  Strings and chars  version 1  string Join  quot  quot   Enumerable Repeat  quot text quot    2           result  texttext  Strings  version 2   String Concat Enumerable Repeat  quot text quot   2      result  texttext  Strings and chars  version 3  new StringBuilder   Insert 0   quot text quot   2  ToString       result  texttext  Chars only   5    3     result  555   Extension way   works FASTER - better for WEB  public static class RepeatExtensions       public static string Repeat this string str  int times                return  new StringBuilder    Insert 0  str  times  ToString             usage   var a    quot Hello quot  Repeat 3       result  HelloHelloHello

User · Answer

Use String PadLeft  if your desired string contains only a single char   public static string Indent int count  char pad        return String Empty PadLeft count  pad       Credit due here

User · Answer

If you re using  NET 4 0  you could use string Concat together with Enumerable Repeat   int N   5     or whatever Console WriteLine string Concat Enumerable Repeat indent  N       Otherwise I d go with something like Adam s answer   The reason I generally wouldn t advise using Andrey s answer is simply that the ToArray   call introduces superfluous overhead that is avoided with the StringBuilder approach suggested by Adam  That said  at least it works without requiring  NET 4 0  and it s quick and easy  and isn t going to kill you if efficiency isn t too much of a concern

User · Answer

I would go for Dan Tao s answer  but if you re not using  NET 4 0 you can do something like that  public static string Repeat this string str  int count        return Enumerable Repeat str  count                        Aggregate                          new StringBuilder str Length   count                            sb  s    gt  sb Append s                         ToString

User · Answer

You can create an ExtensionMethod to do that   public static class StringExtension     public static string Repeat this string str  int count          string ret            for  var x   0  x  lt  count  x                ret    str             return ret          Or using  Dan Tao solution   public static class StringExtension     public static string Repeat this string str  int count          if  count    0        return          return string Concat Enumerable Repeat indent  N

User · Answer

Print a line with repetition   Console Write new string      30      n

User · Answer

Surprised nobody went old-school  I am not making any claims about this code  but just for fun   public static string Repeat this string  this  int count        var dest   new char  this Length   count       for  int i   0  i  lt  dest Length  i    1                dest i     this i    this Length             return new string dest

User · Answer

public static class StringExtensions       public static string Repeat this string input  int count                if   string IsNullOrEmpty input                         StringBuilder builder   new StringBuilder input Length   count                for int i   0  i  lt  count  i    builder Append input                return builder ToString                       return string Empty

User · Answer

I like the answer given  Along the same lines though is what I ve used in the past   quot  quot  PadLeft 3 Indent  -    This will fulfill creating an indent but technically the question was to repeat a string  If the string indent is something like  gt - lt  then this as well as the accepted answer would not work  In this case  c0rd s solution using StringBuilder looks good  though the overhead of StringBuilder may in fact not make it the most performant  One option is to build an array of strings  fill it with indent strings  then concat that  To whit  int Indent   2           string   sarray   new string 6      assuming max of 6 levels of indent  0 based  for  int iter   0  iter  lt  6  iter            using c0rd s stringbuilder concept  insert ABC as the indent characters to demonstrate any string can be used     sarray iter    new StringBuilder   Insert 0   quot ABC quot   iter  ToString       Console WriteLine sarray Indent    quot blah quot       now pretend to output some indented line  We all love a clever solution but sometimes simple is best

User · Answer

I don t have enough rep to comment on Adam s answer  but the best way to do it imo is like this   public static string RepeatString string content  int numTimes            if  string IsNullOrEmpty content   amp  amp  numTimes  gt  0                StringBuilder builder   new StringBuilder content Length   numTimes                for int i   0  i  lt  numTimes  i    builder Append content                return builder ToString                       return string Empty          You must check to see if numTimes is greater then zero  otherwise you will get an exception

User · Answer

Adding the Extension Method I am using all over my projects   public static string Repeat this string text  int count        if   String IsNullOrEmpty text                 return String Concat Enumerable Repeat text  count              return         Hope someone can take use of it

User · Answer

Not sure how this would perform  but it s an easy piece of code    I have probably made it appear more complicated than it is     int indentCount   3  string indent    ---   string stringToBeIndented    Blah      Need dummy char NOT in stringToBeIndented - vertical tab  anyone  char dummy     v   stringToBeIndented PadLeft stringToBeIndented Length   indentCount  dummy  Replace dummy ToString    indent     Alternatively  if you know the maximum number of levels you can expect  you could just declare an array and index into it   You would probably want to make this array static or a constant   string   indents   new string 4        indent  indent Replace  -    --    indent Replace  -    ---    indent Replace  -    ----      output   indents indentCount    stringToBeIndented

User · Answer

I didn t see this solution  I find it simpler for where I currently am in software development   public static void PrintFigure int shapeSize        string figure              for  int loopTwo   1  loopTwo  lt   shapeSize - 1  loopTwo                  Console Write    figure

User · Answer

You can repeat your string  in case it s not a single char  and concat the result  like this   String Concat Enumerable Repeat  ---   5

User · Answer

string indent    ---           string n   string Concat Enumerable Repeat indent  1  ToArray             string n   string Concat Enumerable Repeat indent  2  ToArray             string n   string Concat Enumerable Repeat indent  3  ToArray

User · Answer

Another approach is to consider string as  IEnumerable lt char gt  and have a generic extension method which will multiply the items in a collection by the specified factor   public static IEnumerable lt T gt  Repeat lt T gt  this IEnumerable lt T gt  source  int times        source   source ToArray        return Enumerable Range 0  times  SelectMany     gt  source       So in your case   string indent    ---   var f   string Concat indent Repeat 0       NET 4 required   or var g   new string indent Repeat 5  ToArray

User · Answer

For general use  solutions involving the StringBuilder class are best for repeating multi-character strings  It s optimized to handle the combination of large numbers of strings in a way that simple concatenation can t and that would be difficult or impossible to do more efficiently by hand  The StringBuilder solutions shown here use O N  iterations to complete  a flat rate proportional to the number of times it is repeated   However  for very large number of repeats  or where high levels of efficiency must be squeezed out of it  a better approach is to do something similar to StringBuilder s basic functionality but to produce additional copies from the destination  rather than from the original string  as below       public static string Repeat CharArray LogN this string str  int times                int limit    int Math Log times  2           char   buffer   new char str Length   times           int width   str Length          Array Copy str ToCharArray    buffer  width            for  int index   0  index  lt  limit  index                          Array Copy buffer  0  buffer  width  width               width    2                    Array Copy buffer  0  buffer  width  str Length   times - width            return new string buffer           This doubles the length of the source destination string with each iteration  which saves the overhead of resetting counters each time it would go through the original string  instead smoothly reading through and copying the now much longer string  something that modern processors can do much more efficiently   It uses a base-2 logarithm to find how many times it needs to double the length of the string and then proceeds to do so that many times  Since the remainder to be copied is now less than the total length it is copying from  it can then simply copy a subset of what it has already generated   I have used the Array Copy   method over the use of StringBuilder  as a copying of the content of the StringBuilder into itself would have the overhead of producing a new string  with that content with each iteration  Array Copy   avoids this  while still operating with an extremely high rate of efficiency   This solution takes O 1   log N  iterations to complete  a rate that increases logarithmically  with the number of repeats  doubling the number of repeats equals one additional iteration   a substantial savings over the other methods  which increase proportionally

User · Answer

For many scenarios  this is probably the neatest solution   public static class StringExtensions       public static string Repeat this string s  int n            gt  new StringBuilder s Length   n  Insert 0  s  n  ToString        Usage is then   text    Hello World    Repeat 5     This builds on other answers  particularly  c0rd s   As well as simplicity  it has the following features  which not all the other techniques discussed share    Repetition of a string of any length  not just a character  as requested by the OP   Efficient use of StringBuilder through storage preallocation

[c#] Is there an easy way to return a string repeated X number of times?

Examples related to c#

Examples related to .net