How to Use Wildcards in a String Search Routine

• Microsoft Visual FoxPro for Windows, versions 3.0 and 3.0b

SUMMARY

FoxPro includes several functions, such as AT(), that you can use to determine if a string is contained within another string. However, no native function exists that will use wildcards in the string to be searched for in the larger string. This article shows by example how to search for a string containing wildcards within a larger string.

MORE INFORMATION

Sample Code

FUNCTION wcardfind PARAMETER srchstr, wildcard, longstr

STORE 0    TO ifoundat

   TO inumwcards

STORE 0   TO isrchoffset

   (LEN(wildcard)=1) AND (isrchstrlen>0) TO ok

   STORE 0 TO imatch
   FOR LOOP = 1 TO isrchstrlen
      IF ASC(SUBSTR(srchstr,LOOP,1)) = ;
           ASC(SUBSTR(longstr,LOOP+isrchoffset,1))
         imatch=imatch+1
      ENDIF
   ENDFOR
   IF imatch+inumwcards = isrchstrlen
      lfound = .T.
      ifoundat = isrchoffset+1
   ELSE
      isrchoffset=isrchoffset+1
   ENDIF

Testing the Function

Place the following code before the above function in a program file to test the function. The value returned in the wait window should be 4:

   x1="d?f"
   x2="?"
   x3="abcdefgh"
   xresult=wcardfind(x1,x2,x3)
   wait wind str(xresult)