Why does Stata store Boolean values as float? - storage

I have a variable that looks like this " 88.0*" or " 79.5 " where the asterisk is a flag for something. To extract this flag I run
gen newvar = regexm(oldvar,"\*$")
This works fine, but my new variable is a float, which seems inefficient.
Stata offers storage in byte format, so why doesn't the regexm command (which indicates 0/1 whether a match was found) default to that? For that matter, why doesn't generate (abbreviated gen above) compress the right-hand side by default, or at least as an option?

You can specify the storage type after the gen:
clear
set more off
input ///
str5(var1 var2)
"88.0*" "79.5 "
end
list
gen byte newvar = regexm(var1,"\*$")
list
describe
Note that Stata has no boolean type. A 0 is false, a 1 is true. The syntax for generate is (from help generate):
generate [type] newvar[:lblname] =exp [if] [in]
The type appears between brackets, which means it is an option.
See also help compress to reduce memory used by the data.

Related

Splitting a string variable delimited list into individual binary variables in SPSS

I have a string variable created from a checkbox questions (Which of the following assets do you own?)
I am trying to create individual binary variables for each type of asset based on whether that number is present in the string list.
The syntax I am using cannot differentiate between 1 and 11.
do repeat wrd="1," ",2," ",3," ",4," ",5," ",6," ",7,"/NewVar= W3_CG_asset_TV_1 W3_CG_asset_radio_2 W3_CG_asset_payTV_3 W3_CG_asset_tel_4 W3_CG_asset_cellphone_5
W3_CG_asset_fridge_6 W3_CG_asset_freezer_7.
compute NewVar=char.index(W3_CG_HouseExpen1, wrd)>0.
end repeat.
do repeat wrd= ",8," ",9," ",10," ",11," ",12," ",13," ",14," ",15," ",16," ",17," ",18," ",19," /NewVar= W3_CG_asset_electricstove_8 W3_CG_asset_primusstove_9
W3_CG_asset_gasstove_10 W3_CG_asset_electrickettle_11 W3_CG_asset_microwave_12 W3_CG_asset_computer_13 W3_CG_asset_electricity_14 W3_CG_asset_geyser_15
W3_CG_asset_washingmachine_16 W3_CG_asset_workingvehicle_17 W3_CG_asset_bicycle_18 W3_CG_asset_donkeyhorse_19.
compute NewVar=char.index(W3_CG_HouseExpen1, wrd)>0.
end repeat.
I have tested this on SPSS 28.
make sure the column W3_CG_HouseExpen1 is string and length of it long enough to hold the data.
Then I added execute
data list list/W3_CG_HouseExpen1 (a50).
begin data
"1,2,11,12,"
"2,12,"
"1,2,"
"1,11,12,"
end data.
do repeat
wrd="1," ",2," ",3," ",4," ",5," ",6," ",7," ",8," ",9," ",10," ",11," ",12," ",13," ",14," ",15," ",16," ",17," ",18," ",19,"
/NewVar = W3_CG_asset_TV_1 W3_CG_asset_radio_2 W3_CG_asset_payTV_3 W3_CG_asset_tel_4 W3_CG_asset_cellphone_5 W3_CG_asset_fridge_6 W3_CG_asset_freezer_7
W3_CG_asset_electricstove_8 W3_CG_asset_primusstove_9 W3_CG_asset_gasstove_10 W3_CG_asset_electrickettle_11 W3_CG_asset_microwave_12 W3_CG_asset_computer_13 W3_CG_asset_electricity_14 W3_CG_asset_geyser_15
W3_CG_asset_washingmachine_16 W3_CG_asset_workingvehicle_17 W3_CG_asset_bicycle_18 W3_CG_asset_donkeyhorse_19.
compute NewVar=char.index(W3_CG_HouseExpen1, wrd)>0.
end repeat.
EXECUTE.
My suggestion is to run through this in reverse, erasing the values you've already recognized. So if you've got "11" and erased it, when you later search for "1" you won't find it in an "11".
I recreated a tiny exaple dataset to demonstrate on (EDIT-improved example):
data list list/W3_CG_HouseExpen1 (a50) .
begin data
"1,2,11,12,"
"11,12,"
"2,11,"
end data.
Now I do the whole process on a copy of the original W3_CG_HouseExpen1 variable so I can eat it away without damage to the original data:
string #temp(a50).
compute #temp=W3_CG_HouseExpen1.
do repeat wrd="12," "11," "2," "1," /NewVar= W3_12 W3_11 W3_2 W3_1.
compute NewVar=char.index(#temp, wrd)>0.
compute #temp=replace(#temp, wrd, ""). /*deleting the search string from the full string.
end repeat.
exe.

Other ways to call/eval dynamic strings in Lua?

I am working with a third party device which has some implementation of Lua, and communicates in BACnet. The documentation is pretty janky, not providing any sort of help for any more advanced programming ideas. It's simply, "This is how you set variables...". So, I am trying to just figure it out, and hoping you all can help.
I need to set a long list of variables to certain values. I have a userdata 'ME', with a bunch of variables named MVXX (e.g. - MV21, MV98, MV56, etc).
(This is all kind of background for BACnet.) Variables in BACnet all have 17 'priorities', i.e., every BACnet variable is actually a sort of list of 17 values, with priority 16 being the default. So, typically, if I were to say ME.MV12 = 23, that would set MV12's priority-16 to the desired value of 23.
However, I need to set priority 17. I can do this in the provided Lua implementation, by saying ME.MV12_PV[17] = 23. I can set any of the priorities I want by indexing that PV. (Corollaries - what is PV? What is the underscore? How do I get to these objects? Or are they just interpreted from Lua to some function in C on the backend?)
All this being said, I need to make that variable name dynamic, so that i can set whichever value I need to set, based on some other code. I have made several attempts.
This tells me the object(MV12_PV[17]) does not exist:
x = 12
ME["MV" .. x .. "_PV[17]"] = 23
But this works fine, setting priority 16 to 23:
x = 12
ME["MV" .. x] = 23
I was trying to attempt some sort of what I think is called an evaluation, or eval. But, this just prints out function followed by some random 8 digit number:
x = 12
test = assert(loadstring("MV" .. x .. "_PV[17] = 23"))
print(test)
Any help? Apologies if I am unclear - tbh, I am so far behind the 8-ball I am pretty much grabbing at straws.
Underscores can be part of Lua identifiers (variable and function names). They are just part of the variable name (like letters are) and aren't a special Lua operator like [ and ] are.
In the expression ME.MV12_PV[17] we have ME being an object with a bunch of fields, ME.MV12_PV being an array stored in the "MV12_PV" field of that object and ME.MV12_PV[17] is the 17th slot in that array.
If you want to access fields dynamically, the thing to know is that accessing a field with dot notation in Lua is equivalent to using bracket notation and passing in the field name as a string:
-- The following are all equivalent:
x.foo
x["foo"]
local fieldname = "foo"
x[fieldname]
So in your case you might want to try doing something like this:
local n = 12
ME["MV"..n.."_PV"][17] = 23
BACnet "Commmandable" Objects (e.g. Binary Output, Analog Output, and o[tionally Binary Value, Analog Value and a handful of others) actually have 16 priorities (1-16). The "17th" you are referring to may be the "Relinquish Default", a value that is used if all 16 priorities are set to NULL or "Relinquished".
Perhaps your system will allow you to write to a BACnet Property called "Relinquish Default".

string comparison against factors in Stata

Suppose I have a factor variable with labels "a" "b" and "c" and want to see which observations have a label of "b". Stata refuses to parse
gen isb = myfactor == "b"
Sure, there is literally a "type mismatch", since my factor is encoded as an integer and so cannot be compared to the string "b". However, it wouldn't kill Stata to (i) perform the obvious parse or (ii) provide a translator function so I can write the comparison as label(myfactor) == "b". Using decode to (re)create a string variable defeats the purpose of encoding, which is to save space and make computations more efficient, right?
I hadn't really expected the comparison above to work, but I at least figured there would be a one- or two-line approach. Here is what I have found so far. There is a nice macro ("extended") function that maps the other way (from an integer to a label, seen below as local labi: label ...). Here's the solution using it:
// sample data
clear
input str5 mystr int mynum
a 5
b 5
b 6
c 4
end
encode mystr, gen(myfactor)
// first, how many groups are there?
by myfactor, sort: gen ng = _n == 1
replace ng = sum(ng)
scalar ng = ng[_N]
drop ng
// now, which code corresponds to "b"?
forvalues i = 1/`=ng'{
local labi: label myfactor `i'
if "b" == "`labi'" {
scalar bcode = `i'
break
}
}
di bcode
The second step is what irks me, but I'm sure there's a also faster, more idiomatic way of performing the first step. Can I grab the length of the label vector, for example?
An example:
clear all
set more off
sysuse auto
gen isdom = 1 if foreign == "Domestic":`:value label foreign'
list foreign isdom in 1/60
This creates a variable called isdom and it will equal 1 if foreigns's value label is equal to "Domestic". It uses an extended macro function.
From [U] 18.3.8 Macro expressions:
Also, typing
command that makes reference to `:extended macro function'
is equivalent to
local macroname : extended macro function
command that makes reference to `macroname'
This explains one of the two : in the offered syntax. The other can be explained by
... to specify value labels directly in an expression, rather than through
the underlying numeric value ... You specify the label in double quotes
(""), followed by a colon (:), followed by the name of the value
label.
The quote is from Stata tip 14: Using value labels in expressions, by Kenneth Higbee, The Stata Journal (2004). Freely available at http://www.stata-journal.com/sjpdf.html?articlenum=dm0009
Edit
On computing the number of distinct observations, another way is:
by myfactor, sort: gen ng = _n == 1
count if ng
scalar sc_ng = r(N)
display sc_ng
But yours is fine. In fact, it is documented here: http://www.stata.com/support/faqs/data-management/number-of-distinct-observations/, along with more methods and comments.

how to build complete certificate name, include serial number using openssl's index.txt

Problem Description:
I need to build a regular expression / pattern to find a value that can either be decimal or hex
Background Information:
I am trying to build a lua function that will lookup a cert in index.txt and return the serial number. Ultimately, I need to be able to take the full cert name and run the following command:
openssl x509 -noout -in
/etc/ssl/cert/myusername.6A756C65654063616E2E77746274732E6E6574.8F.crt
-dates
I have the logic to build the file name, all the way up to the serial number... which in the above example, is 8F.
Here's what the index.txt file looks like:
R 140320154649Z 150325040807Z 8E unknown /CN=test#gmail.com/emailAddress=test#gmail.com
V 160324050821Z 8F unknown /CN=test#yahoo.com/emailAddress=test#yahoo.com
V 160324051723Z 90 unknown /CN=test2#yahoo.com/emailAddress=test2#yahoo.com
The serial number is field 4 in the first record, and field 3 in the rest of the records.
According to the documentation https://www.openssl.org/docs/apps/x509.html, serial number can either be hex or decimal.
I'm not quite sure yet how / who determines whether it's hex or decimal (i'm modifying someone else's code that uses openssl)... but I'm wondering if there's a way to check for both. I'll only be checking the value for records that are not Revoked ...aka. ones that do not have "R" in the first column.
Thanks.
Lua unfortunately does not support grouping of patterns, so that you could make the pattern for the second timestamp optional. What you could do is check for the two-timestamp pattern first, and if no match was found (which means that match returns nil), repeat for the one-timestamp pattern:
sn = string.match(line, "^%a%s+%d+Z%s+%d+Z%s+(%x+)")
if not sn then
sn = string.match(line, "^%a%s+%d+Z%s+(%x+)")
end
Note that you could do this all in one line if you're eager:
sn = string.match(line, "^%a%s+%d+Z%s+%d+Z%s+(%x+)") or string.match(line, "^%a%s+%d+Z%s+(%x+)")
Each set of parentheses captures what is matched inside and adds a return value. For more information on patterns in Lua, see the reference manual.
local cert = {
'R 140320154649Z 150325040807Z 8E unknown /CN=test#gmail.com/emailAddress=test#gmail.com',
'V 160324050821Z 8F unknown /CN=test#yahoo.com/emailAddress=test#yahoo.com',
'V 160324051723Z 90 unknown /CN=test2#yahoo.com/emailAddress=test2#yahoo.com'
}
-- for Lua 5.1
for _, crt in ipairs(cert) do
local n3, n4 = crt:match'^%S+%s+%S+%s+(%S+)%s+(%S+)'
local serial = n3:match'^%x+$' or n4:match'^%x+$'
print(serial)
end
-- for Lua 5.2
for _, crt in ipairs(cert) do
local serial = crt:match'^%S+%s+%S+.-%f[%S](%x+)%f[%s]'
print(serial)
end

Read numbers following a keyword into an array in Fortran 90 from a text file

I have many text files of this format
....
<snip>
'FOP' 0.19 1 24 1 25 7 8 /
'FOP' 0.18 1 24 1 25 9 11 /
/
TURX
560231
300244
70029
200250
645257
800191
900333
600334
770291
300335
220287
110262 /
SUBTRACT
'TURX' 'TURY'/
</snip>
......
where the portions I snipped off contain other various data in various formats. The file format is inconsistent (machine generated), the only thing one is assured of is the keyword TURX which may appear more than once. If it appears alone on one line, then the next few lines will contain numbers that I need to fetch into an array. The last number will have a space then a forward slash (/). I can then use this array in other operations afterwards.
How do I "search" or parse a file of unknown format in fortran, and how do I get a loop to fetch the rest of the data, please? I am really new to this and I HAVE to use fortran. Thanks.
Fortran 95 / 2003 have a lot of string and file handling features that make this easier.
For example, this code fragment to process a file of unknown length:
use iso_fortran_env
character (len=100) :: line
integer :: ReadCode
ReadLoop: do
read (75, '(A)', iostat=ReadCode ) line
if ( ReadCode /= 0 ) then
if ( ReadCode == iostat_end ) then
exit ReadLoop
else
write ( *, '( / "Error reading file: ", I0 )' ) ReadCode
stop
end if
end if
! code to process the line ....
end do ReadLoop
Then the "process the line" code can contain several sections depending on a logical variable "Have_TURX". If Have_TRUX is false you are "seeking" ... test whether the line contains "TURX". You could use a plain "==" if TURX is always at the start of the string, or for more generality you could use the intrinsic function "index" to test whether the string "line" contains TURX.
Once the program is in the mode Have_TRUX is true, then you use "internal I/O" to read the numeric value from the string. Since the integers have varying lengths and are left-justified, the easiest way is to use "list-directed I/O": combining these:
read (line, *) integer_variable
Then you could use the intrinsic function "index" again to test whether the string also contains a slash, in which case you change Have_TRUX to false and end reading mode.
If you need to put the numbers into an array, it might be necessary to read the file twice, or to backspace the file, because you will have to allocate the array, and you can't do that until you know the size of the array. Or you could pop the numbers into a linked list, then when you hit the slash allocate the array and fill it from the linked list. Or if there is a known maximum number of values you could use a temporary array, then transfer the numbers to an allocatable output array. This is assuming that you want the output argument of the subroutine be an allocatable array of the correct length, and the it returns one group of numbers per call:
integer, dimension (:), allocatable, intent (out) :: numbers
allocate (numbers (1: HowMany) )
P.S. There is a brief summary of the language features at http://en.wikipedia.org/wiki/Fortran_95_language_features and the gfortran manual has a summary of the intrinsic procedures, from which you can see what built in functions are available for string handling.
I'll give you a nudge in the right direction so that you can finish your project.
Some basics:
Do/While as you'll need some sort of loop
structure to loop through the file
and then over the numbers. There's
no for loop in Fortran, so use this
type.
Read
to read the strings.
To start you need something like this:
program readlines
implicit none
character (len=30) :: rdline
integer,dimension(1000) :: array
! This sets up a character array with 30 positions and an integer array with 1000
!
open(18,file='fileread.txt')
do
read(18,*) rdline
if (trim(rdline).eq.'TURX') exit !loop until the trimmed off portion matches TURX
end do
See this thread for way to turn your strings into integers.
Final edit: Looks like MSB has got most of what I just found out. The iostat argument of the read is the key to it. See this site for a sample program.
Here was my final way around it.
PROGRAM fetchnumbers
implicit none
character (len=50) ::line, numdata
logical ::is_numeric
integer ::I,iost,iost2,counter=0,number
integer, parameter :: long = selected_int_kind(10)
integer, dimension(1000)::numbers !Can the number of numbers be up to 1000?
open(20,file='inputfile.txt') !assuming file is in the same location as program
ReadLoop: do
read(20,*,iostat=iost) line !read data line by line
if (iost .LT. 0) exit !end of file reached before TURX was found
if (len_trim(line)==0) cycle ReadLoop !ignore empty lines
if (index(line, 'TURX').EQ.1) then !prepare to begin capturing
GetNumbers: do
read(20, *,iostat=iost2)numdata !read in the numbers one by one
if (.NOT.is_numeric(numdata)) exit !no more numbers to read
if (iost2 .LT. 0) exit !end of file reached while fetching numbers
read (numdata,*) number !read string value into a number
counter = counter + 1
Storeloop: do I =1,counter
if (I<counter) cycle StoreLoop
numbers(counter)=number !storing data into array
end do StoreLoop
end do GetNumbers
end if
end do ReadLoop
write(*,*) "Numbers are:"
do I=1,counter
write(*,'(I14)') numbers(I)
end do
END PROGRAM fetchnumbers
FUNCTION is_numeric(string)
IMPLICIT NONE
CHARACTER(len=*), INTENT(IN) :: string
LOGICAL :: is_numeric
REAL :: x
INTEGER :: e
is_numeric = .FALSE.
READ(string,*,IOSTAT=e) x
IF (e == 0) is_numeric = .TRUE.
END FUNCTION is_numeric

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