Question

I was using the command ‘string trimright’ to trim my string but I found that this command trims more than required.

My expression is “dssss.dcsss” If I use string trim command to trim the last few characters “.dcsss”, it trims the entire string. How can I deal with this?

Command:

     set a [string trimright "dcssss.dcsss" ".dcsss"]
     puts $a

Intended output:

    dcsss

Actual output

    ""

Answer 1

The string trimright command treats its (optional) last argument as a set of characters to remove (and so .dcsss is the same as sdc. to it), just like string trim and string trimleft do; indeed, string trim is just like using both string trimright and string trimleft in succession. This makes it unsuitable for what you are trying to do; to remove a suffix if it is present, you can use several techniques:

# It looks like we're stripping a filename extension...
puts [file rootname "dcssss.dcsss"]

# Can use a regular expression if we're careful...
puts [regsub {\.dcsss$} "dcssss.dcsss" {}]

# Do everything by hand...
set str "dcssss.dcsss"
if {[string match "*.dcsss" $str]} {
    set str [string range $str 0 end-6]
}
puts $str

If what you’re doing really is filename manipulation, like it looks like, do use the first of these options. The file command has some really useful commands for working with filenames in a cross-platform manner in it.