tcl Substitution


Example

The regsub command is used for regular expression matching and substitution.

set mydata {The yellow dog has the blues.}
# create a new string; only the first match is replaced.
set newdata [regsub {(yellow|blue)} $mydata green]
puts $newdata
The green dog has the blues.
# replace the data in the same string; all matches are replaced
regsub -all {(yellow|blue)} $mydata red mydata
puts $mydata
The red dog has the reds.
# another way to create a new string
regsub {(yellow|blue)} $mydata red mynewdata
puts $mynewdata
The red dog has the blues.

Using back-references to reference matched data.

set mydata {The yellow dog has the blues.}
regsub {(yellow)} $mydata {"\1"} mydata
puts $mydata
The "yellow" dog has the blues.

Documentation: regsub re_syntax