Tcl Question

[David Harrison]

In tcl, how can I check that a variable contains all spaces

Topic

[Tom Rioux]

Hi David,

The following should get you what you want:

[regexp \s+ $a]

Hope this helps…

Tom Rioux

[Anonymous]

Are you wanting to know if it only has spaces ?

Or if it has any spaces ?

[David Harrison]

I want to know if its only spaces.

Tom’s code works if there are any spaces but also other characters

[Anonymous]

I’m sure there are a dozen ways to do this.

But how about this.

string length [string trim $VAR ” “]

If it is zero then it had all blanks or was null

If it has any value then you had non-spaces.

I’m sure Charlie is watching so I’m waiting on his comments on how to improve this.   ❓

[David Harrison]

Yes. That’s what I eventually came up with – and it works.

[Tom Rioux]

If you want just a string of spaces, with no characters, then this should do the trick for you:

regexp “^[ ]+$” $a

Example:

hcitcl>set a ”     “

hcitcl>set b ”   abc”

 abc

hcitcl>regexp “^[ ]+$” $a

1

hcitcl>regexp “^[ ]+$” $b

0

Hope this helps.   Thanks John for pointing out the error of my ways.  Even when I worked for you, you were (and still are) so good at doing that.  I think that makes your day!!!  LOL 😀

[David Harrison]

That’s the one.

Thanks chaps,

Dave

[Charlie Bursell]

If you wanted to know if the string consisted of 0 r more spaces simply:

if {[lempty $var]]} { var is empty or only contains spaces }

If you want to make sure it has at least 1 space but nothing else

if {[string length $var] > 0 && ![regexp — {S} $var]} { var is not empty and contains only spaces}

[Author]

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