I want to print character from the next line:
say :
when this variable dum=183 exists in file , then print the very next charater from next line.
Note : I am using tcl
Thanks,
This should help you get started.
The typical idioms for working with a file one line at a time are:
1) linewise reading:
set f [open thefile.txt]
while {[gets $f line] >= 0} {
# work with the line of text in "line"
}
close $f
2) block reading with line splitting:
set f [open thefile.txt]
set text [read $f]
close $f
set lines [split [string trim $text] \n]
foreach line $lines {
# work with the line of text in "line"
}
This can be simplified by using a package:
package require fileutil
::fileutil::foreachLine line thefile.txt {
# work with the line of text in "line"
}
Another way is to search and extract using a regular expression. This is the worst method as it is inflexible and very likely to be buggy in use.
set f [open thefile.txt]
set text [read $f]
close $f
# this regular expression is an example
if {[regexp {\ydum\y[^\n]*.(.)} $text -> thecharacter]} {
# the character you wanted should be in "thecharacter"
}
Documentation:
>= (operator),
close,
fileutil (package),
foreach,
gets,
if,
open,
package,
read,
regexp,
set,
split,
string,
while,
Syntax of Tcl regular expressions
Related
I'm having a problem that involves an increment of a constant in a VHDL library .vhd file.
I need to create a tcl script that will look for a specific line from the library file:
constant a : integer :=0;
and will increment the 0 to a 1 and the 1 to a 2 with every run of the tcl script.
If the file isn't very large (no more than, oh, 100MB) then the easiest way is to read it all in, find the line, do the update "in place" in memory, and then write it all back out again.
# read the file
set f [open theFile.vhd]
set lines [split [read $f] "\n"]
close $f
# find the line with a regular expression (remember, brace your REs!)
set RE {^\s*constant\s+a\s*:\s*integer\s*:=\s*(\d+)\s*;\s*$}
set idx [lsearch -regexp $lines $RE]
# extract the current value and update it
regexp $RE [lindex $lines $idx] -> value
incr value
# write back into the list of lines
lset lines $idx "constant a:integer := $value;"
# write the lines back to the file
set f [open the file.vhd w]
puts -nonewline $f [join $lines "\n"]
close $f
In this case we are using the regular expression twice, and I made the RE by taking the line and putting in whitespace matchers (\s+/\s*) and number matchers (\d+) in the sensible places.
I have a VHDL file which has a line like this:
constant version_nr :integer := 47;
I want to increment the number in this line in the file. Is there a way to accomplish this with TCL?
This is principally a string operation. The tricky bit is finding the line to operate on and picking the number out of it. This can be occasionally awkward, but it is mainly a matter of choosing a suitable regular expression (as this is the kind of parsing task that they excel at). A raw RE to do the matching would be this:
^\s*constant\s+version_nr\s*:integer\s*:=\s*\d+\s*;\s*$
This is essentially converting all possible places for a whitespace sequence into \s* (except where whitespace is mandatory, which becomes \s+) and matching the number with \d+, i.e., a digit sequence. We then add in parentheses to capture the interesting substrings, which are the prefix, the number, and the suffix:
^(\s*constant\s+version_nr\s*:integer\s*:=\s*)(\d+)(\s*;\s*)$
Now we have enough to make the line transform (which we'll do as a procedure so we can give it a nice name):
proc lineTransform {line} {
set RE {^(\s*constant\s+version_nr\s*:integer\s*:=\s*)(\d+)(\s*;\s*)$}
if {[regexp $RE $line -> prefix number suffix]} {
# If we match, we increment the number...
incr number
# And reconcatenate it with the prefix and suffix to make the new line
set line $prefix$number$suffix
}
return $line
}
In Tcl 8.7 (which you won't be using yet) you can write this as this more succinct form:
proc lineTransform {line} {
# Yes, this version can be a single (long) line if you want
set RE {^(\s*constant\s+version_nr\s*:integer\s*:=\s*)(\d+)(\s*;\s*)$}
regsub -command $RE $line {apply {{- prefix number suffix} {
# Apply the increment when the RE matches and build the resulting line
string cat $prefix [incr number] $suffix
}}}
}
Now that we have a line transform, we've just got to apply that to all the lines of the file. This is easily done with a file that fits in memory (up to a few hundred MB) but requires additional measures for larger files as you need to stream from one file to another:
proc transformSmallFile {filename} {
# Read data into memory first
set f [open $filename]
set data [read $f]
close $f
# Then write it back out, applying the transform as we go
set f [open $filename w]
foreach line [split $data "\n"] {
puts $f [transformLine $line]
}
close $f
}
proc transformLargeFile {filename} {
set fin [open $filename]
# The [file tempfile] command makes working with temporary files easier
set fout [file tempfile tmp [file normalize $filename]]
# A streaming transform; requires that input and output files be different
while {[gets $fin line] >= 0} {
puts $fout [transformLine $line]
}
# Close both channels; flushes everything to disk too
close $fin
close $fout
# Rename our temporary over the original input file, replacing it
file rename $tmp $filename
}
First time poster and new to TCL so please pardon my knowledge.
I've found a few examples on stackoverflow and with that help created a script.
I need to modify few lines of a file, I've tried the following (see code). I can seem to add the line of interest but it does not write it in the correct location e.g. if I want to replace line 3 it adds line after line 3
and moreover deletes subsequent lines if there is more than one line operation.
Lastly could some one kindly suggest the best way to identify the line of interest with name rather than line number. Name is always in the form Filter.HpOrd_n =
where n is 0...k
Data in info.dat
AA
BB
Filter.HpOrd_1 = 2
Filter.HpOrd_2 = 2
Filter.HpOrd_3 = 0.1
Filter.HpOrd_4 = 0.2
CC
DD
EE
FF
Code:
set fd [open "info.dat" r+]
set i 0
while { [gets $fd line] != -1 } {
set line [split $line "\n"]
incr i
if {$i == 3} {
set nLine [lreplace $line 0 0 Filter.LoPass]
puts $fd [join $nLine "\n"]
}
if {$i == 6} {
set nLine [lreplace $line 0 0 Filter.Butterworth]
puts $fd [join $nLine "\n"]
}
}
close $fd
With plain Tcl:
# the input and output file handles
set fin [open info.dat r]
set fout [file tempfile fname]
# process the file
while {[gets $fin line] != -1} {
puts $fout [string map {
"Filter.HpOrd_1" "Filter.LoPass"
"Filter.HpOrd_4" "Filter.Butterworth"
} $line]
}
close $fin
close $fout
# backup the original and overwrite it
file link -hard info.dat.bak info.dat
file rename -force -- $fname info.dat
TCL is just a meta language and set fd [open "info.dat" r+] is related to general file descriptor handling. If you open a file descriptor "r+" you can read and write to that file descriptor, but one file descriptor always points to one point in a file.
With "r+" your file descriptor initially points to the start of the file. Then you gets $fd line a line from the file, so $fd points to the start of the second line afterwards. Now you puts $fs [join $nline "\n"] blindly overwriting from the start of the second line and so on.
Generally you cannot replace lines in one file, but you will write a second file and move that after you closed both files. You can overwrite with seek, but you overwrite from a point in the file. So what you put should always have the same size, of you have read before.
Plain files (in basically all programming languages) are byte/character oriented rather than line oriented. This means 1) that you need to use a seek operation to get back to the beginning of the line you want to overwrite, and 2) unless the new line is exactly the same length as the old one, you will experience stub lines around it.
You have other problems as well. set line [split $line "\n"] doesn't do anything: you've just read line from gets, so it's guaranteed not to have any newlines in it. [join $nLine "\n"] doesn't do what you probably think it does: it will replace any sequences of whitespace in $line with single newlines, but it will not place any newline at the end of the string.
Unless your files are insanely large, I recommend something like this:
Replace by line number
proc lineReplace args {
set lines [split [lindex $args end] \n]
foreach {n line} [lrange $args 0 end-1] {
set index [incr n -1]
if {$index > 0} {
lset lines $index $line
}
}
join $lines \n
}
package require fileutil
fileutil::updateInPlace info.dat {
lineReplace
3 Filter.LoPass
6 Filter.Butterworth
}
In the "front end" you only specify the command to use and thereafter pairs of line number / new line text.
In the "back end" (the lineReplace command) the parameter args will contain those number / line pairs and at the end, as a single item, the complete contents of the file. The file contents are then split into a list of lines, and for every number / line pair you replace one of the items in that list. Finally, the list of lines are joined back into a string with newlines between each line. This string is returned by lineReplace to fileutil::updateInPlace, which replaces the old contents in the file with the returned string.
Replace by name
proc lineReplaceByName args {
set lines [split [lindex $args end] \n]
foreach {name line} [lrange $args 0 end-1] {
set index [lsearch $lines $name*]
if {$index > 0} {
lset lines $index $line
}
}
join $lines \n
}
fileutil::updateInPlace info.dat {
lineReplaceByName
Filter.HpOrd_1 Filter.LoPass
Filter.HpOrd_4 Filter.Butterworth
}
In this case the "back end" calculates the line number by searching for the given name at the beginning of each line. If the name isn't found, the replacement operation is skipped. Otherwise it's the same as before.
Replacing just the name
If you don't want to replace the complete line, but just the name part of it, some changes are necessary. If you are 100% sure that 1) the name never has any whitespace in it, and 2) there is always whitespace between the name and the =, you can just replace lset lines $index $line with lset lines $index 0 $line. If you want to play it safer, you can replace the line with
lset lines $index [regsub {.+(?=\s*=\s*)} [lindex $lines $index] $line]
which uses a regular expression to find the character region that precedes the = character (optionally with whitespace around it) and then replaces that with the text you provided.
The fileutil package is a part of the Tcllib companion library to Tcl.
Documentation: fileutil package, foreach, if, incr, join, lindex, lrange, lsearch, lset, package, proc, regsub, seek, set, split
I have tried the below code, but it is checking line by line and want to check it in whole file. Please help me out in writing the correct code, once i get the pattern break it and says pattern is found else pattern is not found
set search "Severity Level: Critical"
set file [open "outputfile.txt" r]
while {[gets $file data] != -1} {
if {[string match *[string toupper $search]* [string toupper $data]] } {
puts "Found '$search' in the line '$data'"
} else {
puts "Not Found '$search' in the line '$data'"
}
}
If the file is “small” with respect to available memory (e.g., no more than a few hundred megabytes) then the easiest way to find if the string is present is to load it all in with read.
set search "Severity Level: Critical"
set f [open "thefilename.txt"]
set data [read $f]
close $f
set idx [string first $search $data]
if {$idx >= 0} {
puts "Found the search term at character $idx"
# Not quite sure what you'd do with this info...
} else {
puts "Search term not present"
}
If you want to know what line it is in, you might split the data up and then use lsearch with the right options to find it.
set search "Severity Level: Critical"
set f [open "thefilename.txt"]
set data [split [read $f] "\n"]
close $f
set lineidx [lsearch -regexp -- $data ***=$search]
if {$idx >= 0} {
puts "Found the search term at line $lineidx : [lindex $data $lineidx]"
} else {
puts "Search term not present"
}
The ***= is a special escape to say “treat the rest of the RE as literal characters” and it's ideal for the case where you can't be sure that the search term is free of RE metacharacters.
The string first command is very simple, so it's easy to use correctly and to work out whether it can do what you want. The lsearch command is not simple at all, and neither are regular expressions; determining when and how to use them is correspondingly trickier.
I have a file in here which has multiple set statements. However I want to extract the lines of my interest. Can the following code help
set in [open filename r]
seek $in 0 start
while{ [gets $in line ] != -1} {
regexp (line to be extracted)
}
Other solution:
Instead of using gets I prefer using read function to read the whole contents of the file and then process those line by line. So we are in complete control of operation on file by having it as list of lines
set fileName [lindex $argv 0]
catch {set fptr [open $fileName r]} ;
set contents [read -nonewline $fptr] ;#Read the file contents
close $fptr ;#Close the file since it has been read now
set splitCont [split $contents "\n"] ;#Split the files contents on new line
foreach ele $splitCont {
if {[regexp {^set +(\S+) +(.*)} $ele -> name value]} {
puts "The name \"$name\" maps to the value \"$value\""
}
}
How to run this code:
say above code is saved in test.tcl
Then
tclsh test.tcl FileName
FileName is full path of file unless the file is in the same directory where the program is.
First, you don't need to seek to the beginning straight after opening a file for reading; that's where it starts.
Second, the pattern for reading a file is this:
set f [open $filename]
while {[gets $f line] > -1} {
# Process lines
if {[regexp {^set +(\S+) +(.*)} $line -> name value]} {
puts "The name \"$name\" maps to the value \"$value\""
}
}
close $f
OK, that's a very simple RE in the middle there (and for more complicated files you'll need several) but that's the general pattern. Note that, as usual for Tcl, the space after the while command word is important, as is the space between the while expression and the while body. For specific help with what RE to use for particular types of input data, ask further questions here on Stack Overflow.
Yet another solution:
as it looks like the source is a TCL script, create a new safe interpreter using interp which only has the set command exposed (and any others you need), hide all other commands and replace unknown to just skip anything unrecognised. source the input in this interpreter
Here is yet another solution: use the file scanning feature of Tclx. Please look up Tclx for more info. I like this solution for that you can have several scanmatch blocks.
package require Tclx
# Open a file, skip error checking for simplicity
set inputFile [open sample.tcl r]
# Scan the file
set scanHandle [scancontext create]
scanmatch $scanHandle {^\s*set} {
lassign $matchInfo(line) setCmd varName varValue; # parse the line
puts "$varName = $varValue"
}
scanfile $scanHandle $inputFile
close $inputFile
Yet another solution: use the grep command from the fileutil package:
package require fileutil
puts [lindex $argv 0]
set matchedLines [fileutil::grep {^\s*set} [lindex $argv 0]]
foreach line $matchedLines {
# Each line is in format: filename:line, for example
# sample.tcl:set foo bar
set varName [lindex $line 1]
set varValue [lindex $line 2]
puts "$varName = $varValue"
}
I've read your comments so far, and if I understand you correctly your input data file has 6 (or 9, depending which comment) data fields per line, separated by spaces. You want to use a regexp to parse them into 6 (or 9) arrays or lists, one per data field.
If so, I'd try something like this (using lists):
set f [open $filename]
while {[gets $f line] > -1} {
# Process lines
if {[regexp {(\S+) (\S+) (\S+) (\S+) (\S+) (\S+)} $line -> name source drain gate bulk inst]} {
lappend nameL $name
lappend sourceL $source
lappend drainL $drain
lappend gateL $gate
lappend bulkL $bulk
lappend instL $inst
}
}
close $f
Now you should have a set of 6 lists, one per field, with one entry in the list for each item in your input file. To access the i-th name, for example, you grab $nameL[$i].
If (as I suspect) your main goal is to get the parameters of the device whose name is "foo", you'd use a structure like this:
set name "foo"
set i [lsearch $nameL $name]
if {$i != -1} {
set source $sourceL[$i]
} else {
puts "item $name not found."
set source ''
# or set to 0, or whatever "not found" marker you like
}
set File [ open $fileName r ]
while { [ gets $File line ] >= 0 } {
regex {(set) ([a-zA-Z0-0]+) (.*)} $line str1 str2 str3 str4
#str2 contains "set";
#str3 contains variable to be set;
#str4 contains the value to be set;
close $File
}