How to check if a variable is empty in tcl

Question

How can you if the variable is empty? It can contain "\n"

either spaces. I am currently doing this

if {{string trimleft $var} != ""} {
   # the variable is not empty
   puts $var
 }

However, the printed variable still appears to be empty? will trimleft

delete "\n"

? Is there a better way to check if a string is empty?

+3

Rajeshwar Dec 12. 14 at 22:27

2 answers

As far as I know, checking for an empty string is simple:

if {$myString eq ""} {

    puts "string is empty"

}

Doing the following shouldn't print anything:

if {" " eq ""} {
    puts "1"
} elseif {"\n" eq ""} {
    puts "2"
}

I hope I understood your question correctly.

+4

DazedAndConfused Dec 12. 14 at 22:45

Bharathi · Accepted Answer · 2016-03-31T06:24:51+0000

if {{string trimleft "\n"} eq ""} {
    puts "1"
} elseif {"\n" eq ""} {
    puts "2"
}