How to parse file to particular row or upto particular data is received about fast-csv HOT 5 CLOSED

Hi,
I was trying to parse the csv file which is quite big file and i wanted to parse the file upto paritcular point where i get the data i wanted and wanted the parsing to stop after that but there is no option of stopping the parsing and if there is option to stop parsing how to do that .
actually there was one logic i developed to stop the parsing to assume the content after the data wanted to take as comment but i was not able to use that option.

from fast-csv.

http://nodejs.org/api/fs.html#fs_fs_createreadstream_path_options

fs.createReadStream('sample.csv', {start: 0, end: 1000}) //read the first 1000 bytes
  .pipe( csv({headers: true}) )
  .on('data', function(row){
    console.log('Got row', row);
  })

If you want to read exactly half of a file, you can use fs.stat to get the size, then divide it by two.

Note that you may get an invalid row at the end if a row gets cut off in the middle.

from fast-csv.

Thanks for the reply ,
but i wanted to parse like first 20 or may be first 30 rows from csv file .so, how i can get the byte size for these 20 or 30 rows of file.

from fast-csv.

You can't get the byte size for a certain number of rows unless you already know what's in the file, and in order to do that you (usually) have to read the file.

Here's an example which will read 20 rows and then stop.

var fs = require('fs');
var csv = require('fast-csv');

var fileStream = fs.createReadStream('sample.csv', 'utf8');
var csvStream = csv({headers: true});

fileStream.pipe(csvStream);

var rows = [];
var onData = function(row){
  rows.push(row);
  if (rows.length == 20) {
    csvStream.emit('donereading'); //custom event for convenience
  }
};
csvStream.on('data', onData);
csvStream.on('donereading', function(){
  fileStream.close();
  csvStream.removeListener('data', onData);
  console.log('got 20 rows', rows);
});

from fast-csv.

Thanks for Reply.
Problem is solved.

from fast-csv.