regexp and null

[Anonymous]

Clovertechies,

I am having an issue within regexp to compare a null value.

Anyone knows a solution please post. What I am trying to do

is that if the iam_18 field is null then kill it else continue.

for testing purpose I am doing as follows.

None of the values inside the braces able to check the $iam_18

value

hcitcl>set iam_18 “”         <---- This is how I am setting as a null value. Eevn in the HL7, IAM:18 is blank. hcitcl>echo $iam_18

hcitcl>regexp {} $iam_18

0

Thanks in advance.

Reggie

Topic

[Charlie Bursell]

First, you are not sending the variable to null, you are setting it the empty string.  This is a difference.

If you just want to test if it is empty, I prefer to use lempty even though it is a string.  For example:

                      if {[lempty $iam_18]} {d something}

If something else is setting the field to a true null (Hex 00) then test it like:

         if {{regexp — {x00} $iam_18]} {do something}

You really need to use empty string instead of null.  Null has a different connatation.

[Jamin Gray]

If by null you mean an empty string, you don’t need a regular expression to test this.  You could use the string equal command:

Code:

string equal $iam_18 “”

will return 1 if $iam_18 is “” otherwise it’ll return 0

If you really want to use a regular expression:

Code:

regexp {^$} $iam_18

I think what your code is doing is checking if the string matches the null character (octal 0 on the ASCII chart), not checking to see if the string is empty.

[Anonymous]

Thanks Charlie and Jamin for your quick response.

It is really helpful.

-Reggie-

[Author]

Replies