I found an example, with
READ #1 "filename.hex" &data
were &data is a PRACTICE macro. I need to parse this data. As it is stored in a macro, I am not able to. Is it possible to store it in a PRACTICE variable? If so what would the command look like?
You can not read data from a file and store it to a PRACTICE variable directly. However you can read the data to a PRACTICE macro and assign the content of the macro to a PRACTICE variable:
PRIVATE &data // declare macro
VAR.NEWGLOBAL char[64] \mydata // declare variable
READ #1 "filename.hex" &data // read data from file to macro
Var.Set \mydata="&data" // assign content from macro to variable
Note: Macros do only work in PRACTICE script files (*.cmm-files). They do not work in the TRACE32 command line.
Anyhow if you need to parse the data from the file, I would suggest to read-in the complete line from the file to a macro with format option %LINE and then extract the required content from the macro with the STRing-PRACTICE functions like STRing.SPLIT() or STRing.MID() or STRing.SCANAndExtract().
E.g. Get the value from the third column of a CSV file:
PRIVATE &data &value // declare macros
VAR.NEWGLOBAL char[64] \mydata // declare variable
READ #1 "filename.csv" %LINE &data // read one line from file to macro
&value=STRing.TRIM(STRing.SPLIT("&data",",",2)) // get 3rd comma separated value
Var.Set \mydata="&value" // assign content from macro to variable
Related
I have a dataset with a variable called pt with observations 8.1,8.2,8.3 etc and a variable called mean with values like 8.24 8.1 8.234 etc. Which are paired with each other.
I want to be able to set my put informat to the formats from the variable num.
I get the errors "Expecting an arithmetic expression"
"the symbol is not recognized and will be ignored" and "syntax error" from my code. (underlining the &fmt. part)
if pt=&type;
call symput("fmt",pt);
fmt_mean = putn(mean,&fmt.);
Thanks in advance for your help.
The macro processor's work is done before SAS compiles and runs the data step. So trying to place the value into a macro variable and then use it immediately to generate and execute SAS code will not work.
But since you are using the PUTN() function it can use the value of an actual variable, so there is no need to put the format into a macro variable.
fmt_mean = putn(mean,pt);
Please, post your data set and data step. Your description is hard to understand.
However the solution seems to be simple: do not use macro variables! You don't need them here. Unlike put() function which expect format know at compile time (that is when you can use macro variables) its analog putn() expects second argument to be variable. Of course, it works a little slower due to that permittance. So your code can look like that:
data ...;
set ...(keep=mean pt);
fmt_mean = putn(mean, pt);
run;
where pt variable maybe numeric, i.e. 8.2, or character, i.e. '8.2'.
If you want to understand how SAS macro works and what call symput does look here:
https://stackoverflow.com/a/69979074/7864377
I would like to use a variable (its value) as file name. Any ideas? Im using stata 14
Thanks a Lot in advance!
Per the comment from #toonice, please do give more details and I can better address your question.
However, you can use local macros to input into file names. Let's say you have a data set of a single variable x taking values of your filenames. You could loop through the data to save different files with the values of x. For example:
local N = _N
forvalues i = 1/`N' {
local myfilename x[`i']
// Insert code that changes data in some way to make files different
save ../output/`myfilename'_staticfilename.dta, replace
}
Give me more context and I am happy to provide more help.
Using Stata, I define a local macro (macro_name) as a variable (macro_variable) in one data file.
After reading in a new file (in the same do file), I'm no longer able to reference that macro.
Instead, I receive the error:
. di `macro_name'
macro_variable not found
I am learning how to use macros, so please bear with me. However, shouldn't I be able to still display or call on that macro in a single do file even if I load in a new data set?
For example:
use "newdata.dta", clear
This problem occurs regardless of whether I define the macro as a global or local. Additionally, I attempted to solve the problem by creating a separate locals.do file that include in the preamble of my master do file as:
include locals.do
But, I still receive the error listed above.
Do macros (local or global) disappear immediately upon reading in a new file? That doesn't seem right based on what I've read.
Thanks in advance for any clarification.
Consider the following, which points to the source of your problem, and in the last command, reproduces precisely the error message you received.
. do "/var/folders/xr/lm5ccr996k7dspxs35yqzyt80000gp/T//SD08491.000000"
. local macro_name macro_variable
. macro list _macro_name
_macro_name: macro_variable
. display "`macro_name'"
macro_variable
. display `macro_name'
macro_variable not found
r(111);
end of do-file
Added in edit: The above was run from the do-file editor window. When I instead launch Stata and paste the four commands into the command window, running them a line at a time, the following are what results.
. local macro_name macro_variable
. macro list _macro_name
_macro_name: macro_variable
. display "`macro_name'"
macro_variable
. display `macro_name'
macro_variable not found
r(111);
.
At the risk of over-explaining, the point to my original answer is that the error message the displayed in the original post, and in the final command in both of my examples, was due to the failure to include quotation marks in the display command, which caused display to believe that "macro_variable", which was the value assigned to the local macro "macro_name" was not a character string constant, but rather a variable name or scalar, and display was unable to locate a variable or scalar by that name.
Let me add as a bonus explanation that the use of locals.do described in the original post has no hope of working, because local macros are local to the do-file in which they are executed, and vanish at the termination of that do-file. In particular, if you submit a local command by selecting a subset of the lines in the do-file editor window, those lines are copied into a temporary do-file and the values of the local macros vanish at the termination of the temporary do-file.
Generalizing what I wrote in my comment above to Nick:
Macros only maintain the connection between the variable/varlist assigned to a macro name and, therefore, the variable/varlist to which the macro's name refers to must be in memory (i.e. the dataset that contains the variable/varlist has to be in memory) in order to access it via the macro.
Assigning a variable/varlist to a macro does not persist the actual value(s)/element(s) in memory, but rather maintain the connection between the variable/varlist and the macro name assigned to it/them.
I've gone in circles on this one for 1.5 hours, so I'm giving in and asking for help here. What I'm trying to do is dead simple but I cannot for the life of me find a link describing the process.
I have the following data step:
data _null_;
some_date = "01JAN2000"D;
call symput('macro_input_date',left(put(some_date),date9.)));
%useful_macro(¯o_input_date);
run;
where a date value is passed to a macro function (I'm new to these). I'd like to use the numeric value of the date value - let's be wild and say I want to get the value of the year, multiply it by the day value, and subtract the remainder after dividing the month value by 3. I can't seem to get just the year value out of the input. I've tried various things such as
symget, both "naked" and prepended with "%", with arguments that represent all possible permutations of the following variants:
have a naked reference to the variable, e.g. macro_input_date
enclose in single quotes, e.g. 'macro_input_date'
enclose in double quotes, e.g. "macro_input_date"
prepend with the ampersand, e.g. ¯o_input_date
direct call to %sysfunc(year(<argument as variously specified above>)
Can anyone tell me what I am missing?
Thanks!
Given that you asked about macro functions, I'll guess that your example date processing is just an example. Talking about macro functions in general, it's important to understand that a macro function will (generally) not be doing any processing of its own, it will just be generating some data step code to do some task. So, for something like your contrived example, the data step code would be something like:
data out;
set in; * Assume this contains a numeric called 'some_date';
result = year(some_date) * day(some_date) - mod(month(some_date), 3);
run;
To macroise this, you don't need to transfer the data values to the macro, you just need to transfer the variable name:
%macro date_func(var=);
year(&var) * day(&var) - mod(month(&var), 3)
%mend;
data out;
set in; * Assume this contains a numeric called 'some_date';
result = %date_func(var=some_date);
run;
Note that the value of the var parameter here is the literal text some_date, not the value of the some_date data step variable. There are other ways to do it of course - you could actually pass this macro a date literal and it would still work:
data out;
set in; * Assume this contains a numeric called 'some_date';
result = %date_func(var="21apr2017"d);
run;
so it all depends on exactly what you're trying to do... maybe you want to assign the result to another macro variable, so it doesn't need to be part of a data step at all, in which case you could do a similar thing with %sysfunc functions etc.
If you're just trying to get the year, you would do something like:
data _null_;
some_date = "01JAN2000"D;
call symput('macro_input_date',left(put(some_date,date9.)));
yearval = substr(symget('macro_input_date'),6,4);
put yearval=;
run;
Your macro value (¯o_input_date) is not the actual date value (14610) but is the text 01JAN2000. So you cannot use the year function (unless you INPUT it back), you would use substr to grab the year part.
Of course, this is all sort of pointless as going to/from macro variable doesn't really accomplish much here.
Are you just have trouble with date literals? Your data step code
data _null_;
some_date = "01JAN2000"D;
call symput('macro_input_date',left(put(some_date),date9.)));
run;
is just going to do the same thing as
%let macro_input_date=01JAN2000 ;
Now if you want to treat that string of characters as if it represents a date then you need to either wrap it up as a date literal
"¯o_input_date"d
Or convert it.
%sysfunc(inputn(¯o_input_date,date9))
Why not just store the actual date value into the macro variable?
call symputx('macro_input_date',some_date);
Then it wouldn't look like a date to you but it would look like a date to the YEAR() function.
I am trying to write an HDF5 file from C++. The file basically contains a large timeseries matrix in the following format
TimeStamp Property1 Property2
I have managed to write the data successfully, I created a dset and used the H5Dwrite function.
Now my question is how do I create a file header, in other words, if I want to write the following array to the file...
['TimeStamp', 'Property1', 'Property2']
...and tag it to the columns for ease of later use ( I am planning to analyze the matrix in Python). How to do that?
I tried to use H5Dwrite to write a string array but failed, I guess it wanted consistent datatypes, so it just wanted floats, which is the datatype for my data. Then I read about this metadata thing, but I am a bit lost as to how to use it? Any help would be much appreciated.
A related side question is can the first row of a matrix be a string and the others rows contain doubles?
Clean solution(s)
If you store your data as a 1D array of a compound datatype with members TimeStamp, Property1, Property2, etc. then the field names will be stored as metadata and it should be easy to read in Python.
I think there is another clean option but I will just mention it since I never used it myself: HDF5's Table Interface. Read the docs to see if you would prefer to use that.
Direct answers to your question
Now the dirty options: you could add string attributes to your existing dataset. There are multiple ways to do that. You could have a single string attribute with all the field names separated by semicolons, or one attribute per column. I don't recommend it since that would be terribly non-standard.
A related side question is can the first row of a matrix be a string and the others rows contain doubles?
No.
Example using a compound datatype
Assuming you have a struct defined like this:
struct Point { double timestamp, property1, property2; };
and a vector of Points:
std::vector<Point> points;
as well as a dataset dset and appropriate memory and file dataspaces, then you can create a compound datatype like this:
H5::CompType type(sizeof(DataPoint));
type.insertMember("TimeStamp", HOFFSET(Point, timestamp), H5::PredType::NATIVE_DOUBLE);
type.insertMember("Property1", HOFFSET(Point, property1), H5::PredType::NATIVE_DOUBLE);
type.insertMember("Property2", HOFFSET(Point, property2), H5::PredType::NATIVE_DOUBLE);
and write data to file like this:
dset.write(&points[0], type, mem_space, file_space);