STL: Converting a string into a list of string

[blrmaani]

Here is what I want:

string s1 = "This is a list of string";
list<string> s2 = s1.some_method( );

Now, I should be able to traverse list s2 and get each
member ( which is of type 'string' ).
I know that this can be achieved using strtok. But I was wondering
if there is any string member function which returns me a list of string?

thanks in advance
blrmaani

[Russell Hanneken]

blrmaani wrote:

Here is what I want:

string s1 = "This is a list of string";
list<string> s2 = s1.some_method( );

Now, I should be able to traverse list s2 and get each
member ( which is of type 'string' ).

I know that this can be achieved using strtok. But I was wondering
if there is any string member function which returns me a list of string?

There's no string member function that returns a list of strings.

Here are two ways to do what you want (assuming you want to tokenize the
string on whitespace):

SOLUTION 1: Use istringstream

#include <algorithm>
#include <iostream>
#include <iterator>
#include <list>
#include <sstream>
#include <string>

int main()
{
std::string s("This is a list of string");
std::istringstr eam iss(s);

typedef std::istream_it erator<std::str ing> StringReader;
StringReader first(iss);
StringReader last;

// Initialize a list by reading from iss (implicitly using the
// >> operator)
typedef std::list<std:: string> StringList;
StringList myList(first, last);

// Output the contents of the list
typedef std::ostream_it erator<std::str ing> StringWriter;
std::copy (myList.begin() , myList.end(),
StringWriter(st d::cout, "\n"));
}

Here's the output:

This
is
a
list
of
string
SOLUTION 2: Use boost::tokenize r

This is a bit off-topic for this newsgroup, since it involves a
non-standard library. But you might be interested in using the Boost
library's tokenizer template (see http://www.boost.org/).

#include <algorithm>
#include <iostream>
#include <iterator>
#include <list>
#include <string>
#include <boost/tokenizer.hpp>

int main()
{
// Make a tokenizer object from a string (tokenized on
// whitespace)
std::string s("This is a list of string");
boost::tokenize r<> tokens(s);

// Create a list from the tokens
typedef std::list<std:: string> StringList;
StringList myList(tokens.b egin(), tokens.end());

// Output the contents of the list
typedef std::ostream_it erator<std::str ing> StringWriter;
std::copy (myList.begin() , myList.end(),
StringWriter(st d::cout, "\n"));
}

The output:

This
is
a
list
of
string

Hope that helps.

Regards,

Russell Hanneken
rg********@pobo x.com
Remove the 'g' from my address to send me mail.

[David Harmon]

On 27 Apr 2004 12:02:51 -0700 in comp.lang.c++, bl******@yahoo. com
(blrmaani) wrote,

string s1 = "This is a list of string";
list<string> s2 = s1.some_method( );

I would do that using a quickie tokenizer template function such as
http://groups.google.com/gr*********....earthlink.net

[Karthik]

blrmaani wrote:

Here is what I want:

string s1 = "This is a list of string";
list<string> s2 = s1.some_method( );

Now, I should be able to traverse list s2 and get each
member ( which is of type 'string' ).
I know that this can be achieved using strtok. But I was wondering
if there is any string member function which returns me a list of string?

thanks in advance
blrmaani

http://linuxselfhelp.com/HOWTO/C++Pr...g-HOWTO-7.html.

HTH
--
Karthik

Humans please 'removeme_' for my real email.

[Default User]

blrmaani wrote:

Here is what I want:

string s1 = "This is a list of string";
list<string> s2 = s1.some_method( );

Now, I should be able to traverse list s2 and get each
member ( which is of type 'string' ).
Why do you want a list vs. a vector?
I know that this can be achieved using strtok. But I was wondering
if there is any string member function which returns me a list of string?

There's nothing built-in. You can do it yourself by creating a strstream
from the original string and reading in each substring. Alternatively,
I'll give you the Explode() routine I wrote, which works basically like
the one in PHP. I'll leave it as an exercise for you to change it from
vector to list if you are set on that.
#include <vector>
#include <string>

// breaks apart a string into substrings separated by a character string
// does not use a strtok() style list of separator characters
// returns a vector of std::strings

std::vector<std ::string> Explode (const std::string &inString,
const std::string &separator)
{
std::vector<std ::string> returnVector;
std::string::si ze_type start = 0;
std::string::si ze_type end = 0;

while ((end = inString.find (separator, start)) != std::string::np os)
{
returnVector.pu sh_back (inString.subst r (start, end-start));
start = end + separator.size( );
}

returnVector.pu sh_back (inString.subst r (start));

return returnVector;
Brian Rodenborn