How do I check if the content of a variable is numeric?

[macpee]

Hi, everyone. How do I check if the content of a variable is numeric, especially the content of a text box object on the chat? I tried the following but it did not work:

ObjectSetString(0,"SimultaneousReleaseIndex",OBJPROP_TEXT,"Four");

if (MathIsValidNumber(ObjectGetString(0,"SimultaneousReleaseIndex",OBJPROP_TEXT))==true){Print("Object Text Is Numeric");}

If fact it kept indicating true, whether  OBJPROP_TEXT is numeric or not. What could be the solution to the issue. Thanks in advance.

[honest_knave]

MathIsValidNumber doesn't work that way. It wouldn't understand "Four" as 4 anymore than "four" or "FOUR" or "vier" or "quatre" or "quatro".

If you cast "Four" as a double, the result is 0.

As 0 is a valid number, your function returns true.

You will need to build in your own conversions of words to numbers if you want to achieve that. 

Your compiler should have warned you about an implicit conversion ... do you have

#property strict

 at the top of your code?

[macpee]

honest_knave:

MathIsValidNumber doesn't work that way. It wouldn't understand "Four" as 4 anymore than "four" or "FOUR" or "vier" or "quatre" or "quatro".

If you cast "Four" as a double, the result is 0.

As 0 is a valid number, your function returns true.

You will need to build in your own conversions of words to numbers if you want to achieve that. 

Your compiler should have warned you about an implicit conversion ... do you have

#property strict

 at the top of your code?

I think you did not understand the question. I have written the code above and it is expected that the compiler would return false since "Four" is not a number. But it is returning true (meaning that "Four" is a number). How can I code it appropriately? I am not asking to convert "Four" to a number.

[honest_knave]

I think you don't understand the answer 

If you push a string like "Four" or "banana" or "MetaQuotes" into a double the result is 0.

0 is a valid number.

If you were using #property strict your compiler would have alerted you to this issue. 

You can test that the "number" is not 0, but you can't trap whether it was deliberately entered as 0, or it was just converted to 0 in the casting. 

   ObjectSetString(0,"SimultaneousReleaseIndex",OBJPROP_TEXT,"Four");
   double as_double = (double) ObjectGetString(0,"SimultaneousReleaseIndex",OBJPROP_TEXT);
   if(as_double !=0 && MathIsValidNumber(as_double)) Print("Object Text Is Numeric");

[macpee]

honest_knave:

I think you don't understand the answer 

If you push a string like "Four" or "banana" or "MetaQuotes" into a double the result is 0.

0 is a valid number.

If you were using #property strict your compiler would have alerted you to this issue. 

Please check my initial code again. I just made a slight correction. It is supposed to be

ObjectSetString(0,"SimultaneousReleaseIndex",OBJPROP_TEXT,"Four");

and not

ObjectSetInteger(0,"SimultaneousReleaseIndex",OBJPROP_TEXT,"Four");

Sorry for the inconvenience. You may now correct your answer too.  Thanks as I anticipate your kind answer. I don't think I am using #property strict.

[honest_knave]

Please read my post again.

Do you agree that 0 is a valid number? 

[macpee]

honest_knave:

Please read my post again.

Do you agree that 0 is a valid number? 

Of course, 0 is a valid number. Why asking?

[honest_knave]

macpee:
Of course, 0 is a valid number

So which bit of my answer don't you understand?

To re-iterate again:

honest_knave:

If you cast "Four" as a double, the result is 0.

As 0 is a valid number, your function returns true. 

honest_knave:

If you push a string like "Four" or "banana" or "MetaQuotes" into a double the result is 0.

0 is a valid number. 

[macpee]

honest_knave:
So which bit of my answer don't you understand?

But the OBJPROP_TEXT is "Four" and not "0". Also, you said it would regard "Four" as "0" since ...  Now the question is, did I push "Four" to double? Which part of my code pushed "Four" or "banana" or "Metaquote" to double?

[honest_knave]

macpee:
But the OBJ_TEXT is "Four" and not "0". Also, you said it would regard "Four" as "0" since ...  Now the question is, did I push "Four" to double?

If I said make a number out of "sdgfjhsdfkjdshfkjsfdhskdjh" what number would you give me?

[macpee]

honest_knave:

If I said make a number out of "sdgfjhsdfkjdshfkjsfdhskdjh" what number would you give me?

0 of course. But the question corresponding to the code I wrote is that you did not ask me to make a number out of "sdgfjhsdfkjdshfkjsfdhskdjh". But to decide if "sdgfjhsdfkjdshfkjsfdhskdjh" is a number or not. So I think you can make a number out of "sdgfjhsdfkjdshfkjsfdhskdjh". But the fact remains that "sdgfjhsdfkjdshfkjsfdhskdjh" is not a number.