Special characters

[BayzidurRahman]

pattern_id=prxparse('/\b(DEMENTIA|AD DEM|AD WITH|ADVANCED DEM|ALZH|ALZHEIMER\'S|ALZHEIMERS|DEMEN|DEMENTIA\- ALZH|DEMETIA|DEMENI|BPSD|BPDS|BSPD|BSDP|
DEMENTAI|H\/O DEMENETIA)\b/i'); 

I am using the above code to identify some keywords. One of the keywords (ALZHEIMER'S) has apostrophe " ' " in it. I am trying to mask it by using a preceding backslash as I do for other special characters (such as "-")  but it is not working.

[Kurt_Bremser]

Use double quotes on the outside:

pattern_id=prxparse("/\b(DEMENTIA|AD DEM|AD WITH|ADVANCED DEM|ALZH|ALZHEIMER\'S|ALZHEIMERS|DEMEN|DEMENTIA\- ALZH|DEMETIA|DEMENI|BPSD|BPDS|BSPD|BSDP|
DEMENTAI|H\/O DEMENETIA)\b/i"); 

[Tom]

You problem has nothing to do with REGEX, but with basic syntax of how to construct a string constant.

If the character you are using on the outside  to indicate a string constant (either the single quote character, ',  or the double quote character, ") appears in the string then it needs to be doubled up. 

So to make a string constant that contains ALZHEIMER'S  you would need to use one of these two methods:

"ALZHEIMER'S"
'ALZHEIMER''S'

In your case you should change the \' to '' instead.

[BayzidurRahman]

Thanks Tom.