Including local variable in graph title

[Gary Richardson]

I need advice on code for graph titles. I'm making a series of pie charts describing types of events that occurred in 50 year intervals. The code below makes the graphs. I want each graphs' title to reflect the interval. The first interval is 1500 to 1549. The locals y and z contain the correct values as the loop iterates, but they do not appear in the title, which instead reads like " ... temp_y ... ". Any advice on how I could get the titles to display the number (e.g. 1500) rather than temp_y would be appreciated.

Thanks

Gary

forval x=1550(50)1950 {
gen temp_y = `x'-50
local y temp_y
gen temp_y1 = `x'-1
local z temp_y1
graph pie tpre`x'_* if decade==`x'-10, sort descending title("Event Types from `y' to `z'")
drop temp_*
}

[Clyde Schechter]

The commands -local y temp_y- and -local z temp_z- do not put numeric values into local macros y and z. Rather they put the literal strings "temp_y" and "temp_z" in there, respectively. Also, while not causing a problem, there is no point in creating the variables temp_y and temp_y1 unless you have some use for them later. (Even then, since these "variables" are actually constants, it would probably be better to store them as scalars or local macros.)

I think the following code will do what you want:

forvalues x = 1550(50)1950 {
    local y = `x' - 50
    local z = `x' - 1
    graph pie ... title("Event Types from `y' to `z'")
}

Notice the use of the = in the -local- commands here to force evaluation of numbers, rather than putting formula strings into the local macros.

Note: not tested. Beware of typos.

[Gary Richardson]

Thanks Clyde. It worked great.

[Nick Cox]

Did it really work well? By issuing 9 separate pie charts you aren't even guaranteed the same legends -- unless every type of event occurred in every period.

Comparing pie charts is usually hard work. In principle the idea of a pie chart is widely understood; in practice a bar chart is usually easier to think about.

If you give some example data, alternatives can be discussed.

[Gary Richardson]

Hi Nick. Yes, it worked. We are doing pie charts in different chapters of books. Simple to understand, and readers retain information in head across chapters. Gary