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Changes between Version 3 and Version 4 of StringBuilder

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Timestamp:
02/01/14 13:10:25 (4 years ago)
Author:
hopscc
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  • StringBuilder

    v3 v4  
    2323}}} 
    2424 
    25 For more information on the StringBuilder class, see [http://www.google.com/search?hl=en&q=C%23+stringbuilder Google(C# StringBuilder)] 
     25The vernacular notation is something like 
     26 
     27{{{ 
     28sb = StringBuilder() 
     29seperator = '' 
     30for <someloop> 
     31    value = ... some calc or marshalling 
     32    sb.append(sep) 
     33    sep = ',' # or whatever separator is between items 
     34    sb.append(value) 
     35s = sb.toString  # turn into a string for subsequent use 
     36}}} 
     37 
     38= A note about performance = 
     39With string immutability and wrt .Net/C# conventional wisdom has it that use of a !StringBuilder is faster/better performance wise than just catenating to a String type but it depends.... 
     40     
     41    * True, !StringBuilder append is 915-2000x faster than String append but for small strings the overhead of !StringBuilder create  
     42      (and conversion back to String) is much higher (150-180x) than just String create/append... 
     43    * Putting a single string in a !StringBuilder is about 1.6x speed of String doing the same. 
     44      - i.e String append ( {{{ s='...' s+='...'...}}} ) is FASTER than ( {{{ sb=StringBuilder('...'  s.append('...' ...}}} ) 
     45 
     46   * create/append...2 strings in !StringBuilder about same (1.02) speed of String doing same 
     47   * create/append...3,4 strings in !StringBuilder faster (0.92, .8) speed than that of String doing same 
     48    (Without conversion !StringBuilder back to String) 
     49 
     50  Implies use String if appending <=2 strings, !StringBuilder for more and using result directly[[BR]] 
     51  
     52    Full Cycle: create, append, convert to String[[BR]] 
     53        * create, convert to string - using String is about 200x faster than using a !StringBuilder 
     54        * create, append 1 string, convert to String - String about 1.9x faster than !StringBuilder 
     55            - conversion !StringBuilder to String overhead is about 0.3 
     56        * create, append 2 strings, convert to String - using String about 1.13x faster than using !StringBuilder 
     57        * create, append 3 strings, convert to String - using String about 1.2x faster than !StringBuilder 
     58        * create, append 4 strings, convert to String - using String about same (.96, 1.04 slower) speed as  using !StringBuilder  
     59        * create, append 5 strings, convert to string - using String about 0.86 (1.2 slower) than !StringBuilder 
     60 
     61  Implies that it is faster to use String if expecting to append <=4 strings, otherwise use a !StringBuilder ... 
     62 
     63 
     64For more information on the StringBuilder class, see [http://www.google.com/search?hl=en&q=C%23+stringbuilder Google(C# !StringBuilder)] 
    2665 
    2766See also: LibraryTopics