More concise code?

[River Huang]

Dear All, According to the following data

* Example generated by -dataex-. To install: ssc install dataex
clear
input float(id zzmagnitude) int zzinterval1
 1 0   .
 2 2 327
 3 0   .
 4 0   .
 5 0   .
 6 3 284
 7 0   .
 8 3 284
 9 0   .
10 1 272
end

If original zzinterval = 327 and original zzmagnitude = 2, then re-set (change the variable input) the zzinterval to 30 and zzmagnitude = 0. A way to do this is

replace zzinterval1 = 30 if (zzinterval1==327)&(zzmagnitude==2)
replace zzmagnitude = 0 if (zzinterval1==327)&(zzmagnitude==2)

I wonder if there is a more concise way to do this. Thanks.

[Clyde Schechter]

Actually, the code you show will not do what you want. The second replace command will work incorrectly, because after the first command, zzinterval1 will no longer be 327 in the relevant observations. I think you actually need to be a bit more indirect:

gen byte to_change = (zzinterval1 == 327) & (zzmagnitud == 2)
replace zzinterval1 = 30 if to_change
replace zzmagnitude = 0 if to_change

[River Huang]

Dear Clyde, You got me (my bad). Thanks for the correct method.