Parsing string with strtok()

Question

I'm trying to parse this line

Completion_Time_Stamp = 2013-04-04@12:10:22(Eastern Daylight Time)

and put the name in one variable and value in another

token[0] = strtok(buf, " = "); // first token

if (token[0]) // zero if line is blank
{
  for (n = 1; n < 10; n++)
  {
    token[n] = strtok(0, " = "); // subsequent tokens
    if (!token[n]) break; // no more tokens
  }
}

Output :

token[0] = Completion_Time_Stamp
token[1] = 2013-04-04@12:10:22(Eastern
token[2] = Daylight
token[3] = Time)

But I want something like this :

token[0] = Completion_Time_Stamp
token[1] = 2013-04-04@12:10:22(Eastern Daylight Time)

How do I achieve this ? Mutiple delimiters ??

Remember that the second argument is a _set_ of delimiters, it's not the exact delimiter. — Some programmer dude, Apr 04 '13 at 16:53
Regex is serious overkill. You could achieve this with a simple `strstr` call. Also for clarity you should use `NULL` not 0. — Dave, Apr 04 '13 at 16:57
strtok doesn't do what you want. See my answer to http://stackoverflow.com/questions/7136528/string-tokenizer-in-c/7137045#7137045 for strstrtok, which does what you want. — Chris Dodd, Apr 04 '13 at 17:16
Omg they shouldve just made the second argument the exact delimiter ! :D — dharag, Apr 04 '13 at 17:29
You may also find the question [How do I tokenize a string in C++?](http://stackoverflow.com/q/53849/1497596) of interest. — DavidRR, Apr 04 '13 at 18:02

score 4 · Accepted Answer · answered Apr 04 '13 at 16:55

Why not use the functionality that already exists in std::string, like using find and substr.

Something like:

std::string str = "Completion_Time_Stamp = 2013-04-04@12:10:22(Eastern Daylight Time)";

auto delim_pos = str.find('=');

std::string keyword = str.substr(0, delim_pos);
std::string data = str.substr(delim_pos);

Note: The delimiter position (delim_pos in my example) may have to be adjusted when making the substrings.

score 1 · Answer 2 · answered Apr 04 '13 at 16:59

1

You should use just = as your delimiter, and then right trim and left trim your results to get rid of the trailing right space on token 0 and left space on token 1.

answered Apr 04 '13 at 16:59

StarPilot

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Yeah i figured that out and " = " was used to avoid adding trim because from over 200 parameters this is the only one which has spaces in between, but I guess theres no better solution. Thank you. – dharag Apr 04 '13 at 17:15

taocp · Answer 3 · 2013-04-04T17:20:48.033

0

Use std::string, find with arguments "=", then using substring to get those 2 strings.

std::string str1 ="Completion_Time_Stamp = 2013-04-04@12:10:22(Eastern Daylight Time)";
std::string str2 = "=";
std::string part1="";
std::string part2="";

unsigned found = str1.find(str2);
if (found!=std::string::npos) 
{
   part1 = str1.substr(0,found-1);
   part2 = str1.substr(found+2);
}

cout << part1 << "\n" << part2 <<endl;

I got the following:

Completion_Time_Stamp//^^no space here and beginning of second part
2013-04-04@12:10:22(Eastern Daylight Time)

edited Apr 04 '13 at 17:20

answered Apr 04 '13 at 16:57

taocp

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Wouldnt this solution always have an extra space at the end of part1 and beginning of part2 causing problems later ? – dharag Apr 04 '13 at 17:03
@dharag I tested the code posted,you are right, the second substring should start from found +2 to the end of string, while the first one should be found-1 in order to exclude the space. I updated the posted code. – taocp Apr 04 '13 at 17:23

Parsing string with strtok()

3 Answers3