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· Jul 28, 2017

How to detect if string data is number and integer in COS ?

#Beginner #ObjectScript #Caché

Good day,

I would like to know how to detect in Caché ObjectScript if data saved in string is number and furthermore, if it's type is integer.

I maybe found a solution:
 

set value = "44.2d3"

try{
     set status = $INUMBER(value,"")
     if ('$FIND(+value,".")){
          w "your variable: '"_value_"' is number and integer"
     }else{
          w "variable is number but no integer"
     }
}catch(e){
     w "variable is not number" 
}


But I don't know how to do it correctly or if there exist better solution in COS (or maybe my solution is incorrect).

Thanks in advance for answers.

Discussion (10)1
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Marek Bernád Jul 29, 2017 to Robert Cemper


Are you sure that this will work?

USER > set number = "21d20"

USER > if (number\1 = +number) { w "number and integer" } else { w "not number and not integer" }

will output that it is "number and integer", because number\1 will turn string "21d20" to "21" as a result. 
Moreover +number will result from "21d20" to "21" ... and will tell that really 21 equals 21 ... but "21d20" is not number

1 0
Ed de Moel · Jul 28, 2017

Well, that's an interesting one.

One way to check whether the value of a string is a number is:

   If +value=value

which will work in most cases.

However, when the value of a string is something like "1E12345", you'd get an error (<MAXNUMBER>), because "exponential notation" is assumed. But in all other cases, that would work.

Similarly:

   If +value?1.N

Would get close to determining that a value is an integer, but "00000123" would also match that pattern, so

   If value?1.N,+value=value

would do the trick in this case.

Hope this helps

2 0
Alexey Maslov · Aug 1, 2017

If +value=value

This classic code is good for checking if the value is canonical number, while the term number can be interpreted in some other ways, e.g. a number in scientific format, double precision number, etc. Caché has a set of out-of-the-box functions to perform some of these checks, e.g. $isvalidnum, $isvaliddouble, $number, $normalize.

So, the answer depends on topic starter's conditions.

E.g., if I need to check if a number is a numlit (scientific numbers and numbers with starting zeroes are allowed), I'd use `$isvalidnum(x)`. Addition check on being integer (an intlit) can look like: `$isvalidnum(x)&&(+x\1=+x)`. Here are some testing results: 

USER> w !,?6,"Is number?",?20,"Is integer?",?35,"Is canonic?"
USER> for x="001a","002",0,1,"-1.2","+1.3","1E3" w !,x,?10," ",$isvalidnum(x),?20," ",$isvalidnum(x)&&(+x\1=+x),?35,x=+x
 
      Is number?    Is integer?    Is canonic?
001a       0         0             0
002        1         1             0
0          1         1             1
1          1         1             1
-1.2       1         0             1
+1.3       1         0             0
1E3        1         1             0

In other conditions I'd write another code. There is no universal answer to topic starter's question.

P.S. As to "Annotated MUMPS Standard" (http://71.174.62.16/Demo/AnnoStd):
An intlit is not necessarily a canonic representation of a number.

A numlit is not necessarily a canonic representation of a number.

The reduction to a canonical numeric representation involves (colloquially) the removal of any redundant leading and trailing zeroes, the conversion of exponentionential notation to "mantissa only" notation, and the reduction of any leading plus (+) and minus (-) signs to at most one leading minus sign (see also Numeric interpretation of data).

2 0