Gen date variable with missing values

[Raph Selenite]

Hi,
i want to loop to convert my strings data date starting by "d" into date format. But I have variables which have no data and it blocks my loop.
Here is my loop :

unab varlist : d*
foreach x in `varlist'{
gen `x'_2=date(`x',"YMD")
order `x'_2, after(`x')
format `x'_2 %dd_m_y
}


It doesn't work for variable that have 0 value (but it stops my loop...)
For example:

* Example generated by -dataex-. To install: ssc install dataex
clear
input byte d_1 str10 d_2
. "2020-07-17"
. "2020-08-21"
. "2020-07-16"
. "2020-10-01"
end

If i do my loop, it will just stop after the first variable and change nothing
I want this with a loop :

* Example generated by -dataex-. To install: ssc install dataex
clear
input byte d_1 float d_1_2 str10 d_2 float d_2_2
. . "2020-07-17" 22113
. . "2020-08-21" 22148
. . "2020-07-16" 22112
. . "2020-10-01" 22189
end
format %dd_m_y d_2_2

Thanks you !

[Nick Cox]

unab varlist : d*

foreach x in `varlist' {
    gen `x'_2=date(`x',"YMD")
    order `x'_2,after(`x')
    format `x'_2, %dd_m_y
}

The comma in the format statement is illegal. Your code looks fine to me otherwise. It would be fine to go

foreach x of var d* { 

but your version is not wrong.

Note that an empty string variable fed to date() just results in missing dates, so I can't follow your problem report. Also, if your wildcard d* includes any numeric variables, that would be a problem.

[Raph Selenite]

Ok i know, i just used destring all before.... So my variables without data were not string... That was really stupid !
Ty !

[Nick Cox]

ds d*, has(type string) 

filters out the numeric variables. The result is accessible as `r(varlist)',

[Raph Selenite]

Ty this is really good to know !