Extract function return value

[stekicar]

What value extract function returns as in this example?
string_val = abcdef
ret_val=extract(string_val,1,7)

As you can see, extract function should give 7 strings long word but parameter is actually 6 strings long. Is it possible that extract func. returns NULL value?

How can I detect with IF statement the NULL value of ret_val parameter.
Something like this:

if (ret_val==NULL)
DO_THIS */ex.
else
DO_THAT */ex.
endif

 

[looslib]

Check for the length of string_val before obtaining ret_string.
If the length of sring_value is greater than 7, get the first seven characters.
If the length is 7 or less, use string_value as it is.


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

 

[stekicar]

I wanted to check if variable returns NULL as a value so I do not have to do length check. Thank you.

 

[looslib]

string_val = 'abcdef'
ret_val=extract(string_val,1,7)

if (ret_val=='')
result = 'NULL value'
else
result = 'value'
endif

If the length of string_val is less than the extract length, ret_val will be blank.


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli