Invalid Syntax Error while Looping

[Marie Luna]

Hi,

when I enter the following prompt:

* Define periods and variables
local periods "2005 2008 2009 2012 2013 2016 2017 2020 2021 2024"
local vars "debt_maturity_1 size market_to_book leverage rd capex ppe roa dividend_dummy cash age taxes"

* Loop over periods
foreach period in `periods' {
local start = word("`period'", 1)
local end = word("`period'", 2)

* Filter for the time period
preserve
keep if year >= `start' & year <= `end'

* Loop over variables and compute stats for each size group
foreach var in `vars' {
bysort size_group: summarize `var', detail
display "Period: `start'-`end', Variable: `var', Mean: " %9.2f r(mean) ", Median: " %9.2f r(p50)
}

restore
}

I get the Invalid Syntax Error. Any Ideas what I did wrong?

Thanks!

[Seungmin Lee]

What do you want to capture in "start" and "end" local macros?
I ran the first five lines only, and it seems "start" macro captures the year in "periods" macro, while "end" captures nothing.

foreach period in `periods' {
        
    local start = word("`period'", 1)
    local end = word("`period'", 2)
    
    di    "start is `start'"
    di    "end is `end'"
    
}   


start is 2005
end is
start is 2008
end is
start is 2009
end is
start is 2012
end is
start is 2013
end is
start is 2016
end is
start is 2017
end is
start is 2020
end is
start is 2021
end is
start is 2024
end is

I assume this is why you are getting an syntax error in "keep if year >= `start' & year <= `end' line, since you are conditioning on "end" value which is null value.

[Clyde Schechter]

I can tell you what went wrong, but as I'm not sure what you're trying to do, I can't advise you how to fix it.

The error is coming from the command -keep if year >= `start' & year <= `end'-. This is happening because you have defined -local end = word("`period'", 2)-, but local macro period, an iterator in your -foreach- loop is just a single word (number, in your case), so word("`period'", 2) does not exist.

I'll go out on a limb and guess that what you mean to do is have `start' = 2005 with `end' = 2008, and then on the next iteration have `start' = 2008 and `end' = 2009, and so on. If that's the case your code needs start like this:

local n_periods: word count `periods'
local n_periods = `n_periods' - 1
forvalues i = 1/`n_periods' {
    local start = word("`periods'", `i')
    local end = word("`periods'", `=`i'+1')

// ETC.

Note: I haven't really investigated the rest of the code. There may be additional errors in there--at first glance it looks confusing to me, but I haven't checked it out carefully.