Example If Program command throwing up an error of ‘2’ invalid name error

[Veeresh Thummadi]

Hi

I am new in using the program command option. I was checking the power program and i am getting some errors. Can anyone help me why i am getting this errors?

program power
if ‘2’>0 {
generate z=‘1’^‘2’
label variable z "‘1’^‘2’"
}
else if ‘2’==0 {
generate z=log(‘1’)
label variable z "log(‘1’)"
}
else {
generate z=-(‘1’^(‘2’))
label variable z "-‘1’^(‘2’)"
}
end

Then i generated some random values for age and ran the following command

power age 2

I am getting an ‘2’ invalid name error.

Can some one tell me how to fix this?

Thanks
Veeresh

[Joe Canner]

Veeresh,

It looks like you are using the wrong leading quote for the macro 2. It should be `2' which uses the quote that is below the tilde (~) key on the upper left of your keyboard, also known to the French as an accent grave.

Regards,
Joe

[Veeresh Thummadi]

Joe,

I changed the program as per your suggestions but still the error persists. Let me know if there is anything else i can do here?

program power
if `2’>0 {
generate z=`1’^`2’
label variable z "`1’^`2’"
}
else if `2’==0 {
generate z=log(`1’)
label variable z "log(`1’)"
}
else {
generate z=-(`1’^(`2’))
label variable z "-`1’^(`2’)"
}
end

Thanks
Veeresh

[Joe Canner]

Vereesh,

Upon closer inspection, I see that the trailing quote is also incorrect. I'm not sure which one you used, but the correct one is the single quote that is between the colon/semicolon key and the Enter key. It has a double quote when you shift.

Here is the correct version:

program power
if `2'>0 {
generate z=`1'^`2'
label variable z "`1'^`2'"
}
else if `2'==0 {
generate z=log(`1')
label variable z "log(`1')"
}
else {
generate z=-(`1'^(`2'))
label variable z "-`1'^(`2')"
}
end

Regards,
Joe

[Veeresh Thummadi]

Awesome Joe!!! Thanks a lot

[Nick Cox]

As keyboards differ around the world, so too you may need to look in different corners for these keys.

[Veeresh Thummadi]

Hahaa!! They should probably standardize the keyboards!! Actually I didn't type the code, I just copy pasted from the stata help file and was not sure why it was throwing up error. Too many eyeballs are really helpful!!

[Veeresh Thummadi]

I was actually trying to use this program to write a code for regressing for only certain observations like if qualifiers(say if foreign==0). I have a lot of regressions and code and so i didn't want to put the if qualifier behind every line of code in between { }. After running the code i realized that if at the top of the program is not helping it to function as if qualifier. Is there a way i can restrict the observations like if qualifier at the top of the program?


program power if `2'==0 { regress mpg mass } end power foreign 2

[Veeresh Thummadi]

Here is the code:

program power if `2'==0 {
regress mpg mass
}
end

power foreign 2

[Joe Canner]

Veeresh,

It sounds like what you want is this:

program power
regress mpg mass if `2'==0
end

However, you should also check out the syntax command which allows subsetting of observations using the Stata in qualifier. For example:

program test
syntax varlist [if] [in]
regress `varlist' `if' `in'
end

. test a b c if z==0

See also the marksample command which provides additional flexibility.

Regards,
Joe