>>I want to compare two arrays to see if one
>>is different. What is the best way?
>
>Try the following in a function. llresult will return .T. if the arrays are identical.
>
>LPARAMETERS parray1, parray2
>
>LOCAL llresult, lnlast1, lnlast2, lni
>lnlast1 = ALEN(parray1)
>lnlast2 = ALEN(parray2)
>lni = 0
>llresult = (lnlast1 = lnlast2)
>DO WHILE llresult AND lni < lnlast
> lni = lni + 1
> llresult = (parray1[lni] = parray2[lni])
>ENDDO
>RETURN llresult
>
>hth,
>
>George


I would change it slightly to improve performance by letting vfp do the incrementing and letting the user select starting the compare loop at the bottom if that is where the difference is most likely to occur (need speed!!):

LPARAMETERS parray1, parray2, top_bottom

if parameters() < 3
top_bottom = 0 && start at top (1)
endif

LOCAL lnlast1, lnlast2, lni

lnlast1 = ALEN(parray1)
lnlast2 = ALEN(parray2)

do case

case (lnlast1 != lnlast2)
return .f.

case top_bottom != 0

for lni = lnLast1 to 1 step -1
if (parray1[lni] != parray2[lni])
return .f.
endif
endfor

otherwise

for lni = 1 to lnLast1
if (parray1[lni] != parray2[lni])
return .f.
endif
endfor

endcase

RETURN .t.