nixCraft

I have floating point data (193 rows & 2 column in a file from which i would like to delete every row except some required rows. I have written a test.sed file which had
' pattern1/p'
' pattern2/p'
.....
and after that used
sed -f test.sed input_file > output
however this was not appending the whole input file to the output file but my required patterns were written twice in the output.
How do i delete all other lines(row.......?

use

all the needed patterns are in output_file.

got a new problem, in my test.sed file i used the pattern /0.400/p to get the two columns with 0.400 in column one. however i also have a 14.400 in the input file.
now the 14.400 and its corresponding column two also got copied to the output file. This also happened with two other values........is there a way that i can select only 0.400 and not 14.400 or 3.400 ?

Well create file and then omit those file with grep or better write awk script. Whenever you have colum based data it is better to use awk, IMPO.

data reads different in C program
I wrote a Cprogram to just read the output file created using our above sed lines.
the output file was 12703 bytes after removing ^M (discussed in our forum topic 'contents of file') the total no of floating pt data is 1760.
So diving file size by 1760, i get 7.2176 bytes per each data. i dont know how many bytes shell script used to represent floating pt.
I declared malloc for double data. then read 7 bytes and printed it..........some differnt data got printed. then i tried reading 6 bytes & 4 bytes still it did not work.

does this mean the output file created by shell is in a different format??

data reads different in C program
I wrote a Cprogram to just read the output file created using our above sed lines.
the output file was 12703 bytes after removing ^M (discussed in our forum topic 'contents of file') the total no of floating pt data is 1760.
So diving file size by 1760, i get 7.2176 bytes per each data. i dont know how many bytes shell script used to represent floating pt.
I declared malloc for double data. then read 7 bytes and printed it..........some differnt data got printed. then i tried reading 6 bytes & 4 bytes still it did not work.

does this mean the output file created by shell is in a different format??

Data should remain same even if you use the shell script or C program. It should not change it. Can you put your sample input data as well as what output you need from that data. Btw I also love to do C coding. It is kind of fun not a big programmer but for fun only.

hi,
ya i acutally got the solution. shell wrote the output file as characters. so if data was 16.2345 then the seven characters each had one byte and that y my file size was about 1760x7.something(decimal) data in the c code i was reading float data using read(fp,buf,sizeof(float)) and this was giving me trash.
Now i changed the code to
the data in f was float and then when i wrote all data to a new file, this time the file size was exactly 1760(float data) x 4 = 7040.
Can give me a small C program to draw a graph. As i mentioned in the beginning, i have 2 columns of data and i just want to plot a graph in C with colm 1 as x axis and all the different column 2's from all the .txt files as y axis. Note: column 1 data is same in all .txt files.

Okay try out following urls

Plplot online doc: http://plplot.sourceforge.net/docboo...lot-html-5.5.3

An example of Plplot: http://plplot.sourceforge.net/examples/index.html

Try it and lemme know it...