CODEWITHSUNDEEP
cregexstringscanf
Fernando
Fernando

Reputation: 7905

Extract string pattern in C (no libs)

I'm reading a file with the following format:

    /* ...more text above */
    [Text=WORKING CharacterOffsetBegin=73516 CharacterOffsetEnd=73523 PartOfSpeech=VBG                 
    Lemma=work] [Text=MEN CharacterOffsetBegin=73524 CharacterOffsetEnd=73527                    
    PartOfSpeech=NNS Lemma=man] [Text=OF CharacterOffsetBegin=73528
    CharacterOffsetEnd=73530 PartOfSpeech=IN Lemma=of] [Text=ALL
    CharacterOffsetBegin=73531 CharacterOffsetEnd=73534 PartOfSpeech=NN Lemma=all] 
    [Text=COUNTRIES CharacterOffsetBegin=73535 CharacterOffsetEnd=73544 PartOfSpeech=NNS 
    Lemma=country] [Text=, CharacterOffsetBegin=73544 CharacterOffsetEnd=73545
    PartOfSpeech=, Lemma=,] [Text=UNITE CharacterOffsetBegin=73546
    CharacterOffsetEnd=73551 PartOfSpeech=VB Lemma=unite] [Text=!
    CharacterOffsetBegin=73551 CharacterOffsetEnd=73552 PartOfSpeech=. Lemma=!]
    /* ...more text below */

What i want to do is to extract into an array the strings given by Text= and Lemma=. For example, for the text above the output would be:

 WORKING
 work
 MEN
 man
 OF
 of

And so on. What i've tried:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_LINE 4096

int main()
{
  FILE *fp;
  fp = fopen("moby.txt.out", "r");

  char *linha = malloc(MAX_LINE);
  int s, t;
  char lemma[100];

  while(fgets(linha, MAX_LINE, fp))
  {
    if(sscanf(linha, "Sentence #%d (%d tokens):", &s, &t))
    {
      /*printf("%d\n", t);*/
    }
    else if(sscanf(linha, "Lemma=%s", lemma))
    {
      printf("%s", lemma);
    }
}

fclose(fp);
return 0;
}

I can't use external libs. I know regex is not part of C language, so any help is welcome.

Thanks!

Upvotes: 1

Views: 432

Answers (1)

user529758
user529758

Reputation:

And anyways you don't even need regexes. Nor scanf(). A simple solution is using strstr().

const char *s = "[Text=WORKING CharacterOffsetBegin=73516 CharacterOffsetEnd=73523 PartOfSpeech=VBG \
    Lemma=work] [Text=MEN CharacterOffsetBegin=73524 CharacterOffsetEnd=73527 \
    PartOfSpeech=NNS Lemma=man]";

const char *p = s;
while ((p = strstr(p, "Text=")) != NULL) {
    p += 5;
    const char *t = strchr(p, ' ');
    printf("%.*s\n", (int)(t - p), p);

    p = strstr(t + 1, "Lemma=") + 6;
    t = strchr(p, ']');
    printf("%.*s\n", (int)(t - p), p);
    p = t + 1;
}

Upvotes: 8

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