egghelp/eggheads community

Reading last 20 lines from file

2004-10-18T00:02:49-04:00

Code:

proc readLines {f n} {  if {![catch {open $f r} rf]} {    set c [read $rf]    set l [expr ([llength $c] - $n]) - 1];# i think llength includes 0 so..    if {$l <= 0} {      foreach x [split $c \n] {        puts $x      }      close $rf      return     }    foreach x [split $c \n] {      if {[info exists i]} {        incr i      } else {      set i 0      }      if {($i >= $l)} {        puts "$x"      }    }    close $rf  } else {    error "Couldn't open $f.."  }}readLines  <20>

i think this works haven't tested it tho

Statistics: Posted by Ofloo — Mon Oct 18, 2004 12:02 am

Re: Reading last 20 lines from file

2004-10-16T00:22:14-04:00

What would be the best way to go about reading the last 20 lines from a txt file?

The only thing I can think of is, check how many lines there are, and make it read the last 20 ones. Which involves a calculation for each line read...problem is - I'm not able to put it into code. Does anybody know a way to do this...or even a better way to read last 20 lines?

Thanks, later.

If your file is not too big, you can use a simple procedure.

- [read] in the complete file at once
- [split] the file into a list around the newline character
- take the last 20 elements of that list

done.

Statistics: Posted by egghead — Sat Oct 16, 2004 12:22 am

Reading last 20 lines from file

2004-10-15T21:18:47-04:00

What would be the best way to go about reading the last 20 lines from a txt file?

The only thing I can think of is, check how many lines there are, and make it read the last 20 ones. Which involves a calculation for each line read...problem is - I'm not able to put it into code. Does anybody know a way to do this...or even a better way to read last 20 lines?

Thanks, later.

Statistics: Posted by Guest — Fri Oct 15, 2004 9:18 pm