I found a thread regarding this from 11 years ago, but couldn't find anything else so thought it may be best to check if the newer versions of FM have a solution to this problem. Is there any function or custom function that would allow me to check if the value in a field is numeric? I have a field that is supposed to be only numeric (primarily only positive integers) however occasionally there are entries like '1 + 4' or '10 + 2'. I'd like to enter the contents of this field into another field, but only with the entries that are numeric only. Any thoughts? Really appreciate any help.

Hi Eli

I know someone will have a better answer than this, but my thoughts would be 

1) Make the field type be 'number' and use the fields options validation set to 'Strict Data Type = Numeric'

2) If the field has to be a text field, but you want to check that it is numeric, the you could do something like :-
 

FieldIsNumber = If ( Filter ( numberField ; "0123456789" ) = numberField ; 1 ; 0 )

This Boolean result would be 1 if the field only contained numerals. It would give a positive result for '01234', but this may be OK.

Edited July 10, 20187 yr by rwoods

I'm assuming the field you refer to is defined as a text field. The test below is based on this.

A test for a TEXT field's contents being purely numeric is:

GetAsNumber ( Field) = Field

An example:  If a text field contains the value:  1+4

GetAsNumber (1+4) = 14 returns false, therefore the value '1+4' would be excluded for you.

On the other hand, GetAsNumber (18) = 18 returns true, therefore the value '18' would be accepted.

But if your field is defined as a number field, a more stringent test needs to be used such as:

GetAsNumber ( Field) = Field and Length(GetAsNumber ( Field)) = Length(Field)

Ralph

Edited July 10, 20187 yr by NLR

You might also try the Filter Funtion

Filter ( yourField ; "0123456789" )

Thanks everyone for all the suggestions, these are all very helpful and have solved my problem. Really appreciate it!

On 7/10/2018 at 6:18 PM, rwoods said:

Hi Eli

I know someone will have a better answer than this, but my thoughts would be 

1) Make the field type be 'number' and use the fields options validation set to 'Strict Data Type = Numeric'

2) If the field has to be a text field, but you want to check that it is numeric, the you could do something like :-
 

FieldIsNumber = If ( Filter ( numberField ; "0123456789" ) = numberField ; 1 ; 0 )

This Boolean result would be 1 if the field only contained numerals. It would give a positive result for '01234', but this may be OK.

FieldIsNumber would return false for 1.0 (or 1,5 depending on your language) so make sure you include the dot and/or comma as well in the filter.

Good point @OlgerDiekstra

It certainly needs the decimal delimiter in the Filter list!