How to convert string variable to number?

Hi,

TCL variables are loosely typed so I don't think you necessarily would need to convert a string to an integer:

 
 % expr {7 % 4} 
 3 
 % expr {0 % 4} 
 0 
 % expr {"7" % 4} 
 3 
 % expr {"7" % "4"} 
 3 
 

What types of values are you trying to mod? What issues/errors are you seeing?

You do need to be careful in some scenarios when performing comparisons or operations though. Joe posted an article which describes some of this:

http://devcentral.f5.com/Default.aspx?tabid=63&articleType=ArticleView&articleId=281

7 - Understand Polymorphism

TCL is polymorphic in that variables can "morph" back and forth from data type to data type depending on how it is used. This makes loosly-typed languages like TCL easier to work with since you don't need to declare variables as a certain type such as integer or string but it does come at a cost. You can minimize those costs by using the correct operators on your data types.

* Use the correct operator for the correct type.

* Use eq,ne when comparing strings.

* Use ==,!= when comparing numbers

* Use [IP::addr] when comparing IP addresses.

If you aren't careful, things may not be what they seem as illustrated below

set x 5

if { $x == 5 } { } evaluates to true

if { $x eq 5 } { } evaluates to true

if { $x == 05 } { } evaluates to true

if { $x eq 05 } { } evaluates to false

Aaron

Hi, Aaron,

 

From example below.

 

I try to mod string type($subid) by 4 but I'm not sure that what type will return?

 

 

set subid [findstr [HTTP::payload] "subscriberNumber" 0 ""]

 

set modid expr {$subid % 4}

 

 

 

Thank you,

 

Paritchaya

Hi Paritchaya,

 

 

What is the value for subid? Or what is the full HTTP payload?

 

 

I think TCL will try to convert it to an integer if you're using the variable in a mod operation.

 

 

Aaron