Re: [Boost-users] Using Boost string library

Boris Gubenko wrote:

I may be overlooking something, and I hate to say it on the boost mailing list, but it seems to me that strcoll() C function does exactly what you need.

I think I know what I'm overlooking: the integers in your strings are not all single-digit integers as in your examples. If this is correct, I retract my strcoll() proposal. Sorry for the confusion. Boris ----- Original Message ----- From: "Boris Gubenko" To: Cc: "Boris Gubenko" Sent: Saturday, February 17, 2007 11:44 PM Subject: Re: [Boost-users] Using Boost string library

I may be overlooking something, and I hate to say it on the boost mailing list, but it seems to me that strcoll() C function does exactly what you need.

Thanks, Boris

----- Original Message ----- From: "Meryl Silverburgh" To: Sent: Saturday, February 17, 2007 8:52 PM Subject: Re: [Boost-users] Using Boost string library

...

Thanks for your idea.

I have cases like this:

/1/1 /1/2/3/2

Since the first string /1/1 is smaller than the /1/2 (1 is < 2) of the /1/2/3/2, I should able to stop comparison by looking at the 4th character (/1/2) of '/1/2/3/2'.

So for cases like that, I would like to stop as soon as i can tell one string is shorter than the other, instead of splitting the whole string.

On 2/17/07, Pavol Droba wrote:

...

Hi,

Meryl Silverburgh wrote:

...

Hi,

I need to compare 2 strings in this format (a integer separator by '/': /1/1 /1/1/2 /1/1/3

so "/1/1" is less than "/1/1/2" and "/1/1/2" is less than " "/1/1/3".

Is there anything in Boost string library to help me to write such a comparison? Is there a string iterator which literates base on the separator '/'? My idea is to find an iterator to loop thru the string based on separator '/'.

There is a split_iterator which you can use. And there is a generic lexicographical_compare function.

I've got an idea that might work. But it is a little elaborate. First, tokenize your string using split, but store the result to vector.

Then define a comparison function, that will take the two iterator_ranges and compare them. Note, that in this case, tha range should hold an integer string. Then simply use lexicographical_compare for the comparison.

vector vec1; split(vec, s1); vector vec2; split(vec, s2); if(lexicographical_compare(vec1, vec2, integer_compare)) { // s1 is less }

You can even throw away the vector, and directly create an iterator_range from the split_iterator. This way you may spare some unnecessary tokenization.

typedef split_iteratorstring::const_iterator string_split; iterator_range r1( make_split_iterator(s1, is_any_of("/")), string_split())

iterator_range r2( make_split_iterator(s2, is_any_of("/")), string_split())

if(lexicographical_compare(vec1, vec2, integer_compare)) { // s1 is less }

Best Regards, Pavol. _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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