Tokenize a string

Tokenize a string
You are encouraged to solve this task according to the task description, using any language you may know.

Separate the string "Hello,How,Are,You,Today" by commas into an array so that each index of the array stores a different word. Display the words to the 'user', in the simplest manner possible, separated by a period. To simplify, you may display a trailing period.

Ada

with Ada.Strings.Fixed; use Ada.Strings.Fixed;
with Ada.Text_Io; use Ada.Text_Io;

procedure Parse_Commas is
   Source_String : String := "Hello,How,Are,You,Today";
   Index_List : array(1..256) of Natural;
   Next_Index : Natural := 1;
begin
   Index_List(Next_Index) := 1;
   while Index_List(Next_Index) < Source_String'Last loop
      Next_Index := Next_Index + 1;
      Index_List(Next_Index) := 1 + Index(Source_String(Index_List(Next_Index - 1)..Source_String'Last), ",");
      if Index_List(Next_Index) = 1 then 
         Index_List(Next_Index) := Source_String'Last + 2;
      end if;
      Put(Source_String(Index_List(Next_Index - 1)..Index_List(Next_Index)-2) & ".");
   end loop;
end Parse_Commas;

C++

Standard: ANSI C++

Compiler: GCC g++ (GCC) 3.4.4 (cygming special)

Library: STL

This is not the most efficient method as it involves redundant copies in the background, but it is very easy to use. In most cases it will be a good choice as long as it is not used as an inner loop in a performance critical system.

Note doxygen tags in comments before function, describing details of interface.

#include <string>
#include <vector>
/// \brief convert input string into vector of string tokens
///
/// \note consecutive delimiters will be treated as single delimiter
/// \note delimiters are _not_ included in return data
///
/// \param input string to be parsed
/// \param delims list of delimiters.

std::vector<std::string> tokenize_str(const std::string & str,
                                      const std::string & delims=", \t")
{
  using namespace std;
  // Skip delims at beginning, find start of first token
  string::size_type lastPos = str.find_first_not_of(delims, 0);
  // Find next delimiter @ end of token
  string::size_type pos     = str.find_first_of(delims, lastPos);

  // output vector
  vector<string> tokens;

  while (string::npos != pos || string::npos != lastPos)
    {
      // Found a token, add it to the vector.
      tokens.push_back(str.substr(lastPos, pos - lastPos));
      // Skip delims.  Note the "not_of". this is beginning of token
      lastPos = str.find_first_not_of(delims, pos);
      // Find next delimiter at end of token.
      pos     = str.find_first_of(delims, lastPos);
    }

  return tokens;
}

here is sample usage code:

#include <iostream>
int main() {
  using namespace std;
  string s("Hello,How,Are,You,Today");

  vector<string> v(tokenize_str(s));

  for (unsigned i  = 0; i < v.size(); i++) 
    cout << v[i] << ".";
  
  cout << endl;
  return 0;
}

E

".".rjoin("Hello,How,Are,You,Today".split(","))

Java

Compiler: JDK 1.0 and up

There is multiple way to tokenized a string in Java. The first with a split the String into an array of String, and the other way to give a Enumerator. The second way given here will skip any empty token. So if two commas are given in line, there will be an empty string in the array given by the split function but no empty string with the StringTokenizer object.

String toTokenize = "Hello,How,Are,You,Today";

//First way
String word[] = toTokenize.split(",");
for(int i=0; i<word.length; i++) {
    System.out.print(word[i] + ".");
}
       
//Second way
StringTokenizer tokenizer = new StringTokenizer(toTokenize, ",");
while(tokenizer.hasMoreTokens()) {
    System.out.print(tokenizer.nextToken() + ".");
}

JavaScript

Interpreter: Firefox 2.0

var str = "Hello,How,Are,You,Today";
var tokens = str.split(",");
alert( tokens.join(".") );

Perl

Interpreter: Perl any 5.X

As a one liner without a trailing period, and most efficient way of doing it as you don't have to define an array.

print join('.', split(/,/, "Hello,How,Are,You,Today"));

If you needed to keep an array for later use, again no trailing period

my @words = split(/,/, "Hello,How,Are,You,Today");
print join('.', @words);

If you really want a trailing period, here is an example

my @words = split(/,/, "Hello,How,Are,You,Today");
print $_.'.' for (@words);

PHP

Interpreter: PHP any 5.x

<?php
$str = 'Hello,How,Are,You,Today';
$arr = array_fill_keys(explode(',', $str), 0);
echo implode('.', array_keys($arr));
?>

Python

Interpreter: Python 2.5

 words = "Hello,How,Are,You,Today"
 list_of_words = words.split(',')
 print '.'.join(list_of_words)

If you want to print each word on its own line:

 for word in list_of_words:
     print word

or

 print "\n".join(list_of_words)

Ruby

    string = "Hello,How,Are,You,Today".split(',')
    string.each do |w|
         print "#{w}."
    end

Seed7

var array string: tokens is 0 times "";

tokens := split("Hello,How,Are,You,Today", ",");

Standard ML

val splitter = String.tokens (fn c => c = #",");
val main = (String.concatWith ".") o splitter;

Test:

- main "Hello,How,Are,You,Today"
val it = "Hello.How.Are.You.Today" : string

Tcl

Generating a list form a string by splitting on a comma:

 split string ,

Joining the elements of a list by a period:

 join list .

Thus the whole thing would look like this:

 puts [join [split "Hello,How,Are,You,Today" ,] .]

If you'd like to retain the list in a variable with the name "words", it would only be marginally more complex:

 puts [join [set words [split "Hello,How,Are,You,Today" ,]] .]