When I´m using MATLAB, sometimes I feel the need to make comments on some variables. I would like to save these comments inside these variables. So when I have to work with many variables in the workspace, and I forget the context of some of these variables I could read the comments I put in every one of them. So I would like to comment variables and keep the comments inside of them.
While I'm of the opinion that the best (and easiest) approach would be to make your variables self-documenting by giving them descriptive names, there is actually a way for you to do what you want using the object-oriented aspects of MATLAB. Specifically, you can create a new class which subclasses a built-in class so that it has an additional property describing the variable.
In fact, there is an example in the documentation that does exactly what you want. It creates a new class ExtendDouble that behaves just like a double except that it has a DataString property attached to it which describes the data in the variable. Using this subclass, you can do things like the following:
N = ExtendDouble(10,'The number of data points')
N =
The number of data points
10
and N could be used in expressions just as any double value would. Using this example subclass as a template, you could create "commented" versions of other built-in numeric classes, with the exception of those you are not allowed to subclass (char, cell, struct, and function_handle).
Of course, it should be noted that instead of using the ExtendDouble class like I did in the above example, I could instead define my variable like so:
nDataPoints = 10;
which makes the variable self-documenting, albeit with a little more typing needed. ;)
How about declaring another variable for your comments?
example:
\>> num = 5;
\>> numc = 'This is a number that contains 5';
\>> whos
...
This is my first post in StackOverflow. Thanks.
A convenient way to solve this is to have a function that does the storing and displaying of comments for you, i.e. something like the function below that will pop open a dialog box if you call it with comments('myVar') to allow you to enter new (or read/update previous) comments to variable (or function, or co-worker) labeled myVar.
Note that the comments will not be available in your next Matlab session. To make this happen, you have to add save/load functionality to comments (i.e. every time you change anything, you write to a file, and any time you start the function and database is empty, you load the file if possible).
function comments(name)
%COMMENTS stores comments for a matlab session
%
% comments(name) adds or updates a comment stored with the label "name"
%
% comments prints all the current comments
%# database is a n-by-2 cell array with {label, comment}
persistent database
%# check input and decide what to do
if nargin < 1 || isempty(name)
printDatabase;
else
updateDatabase;
end
function printDatabase
%# prints the database
if isempty(database)
fprintf('no comments stored yet\n')
else
for i=1:size(database,1)
fprintf('%20s : %s\n',database{i,1},database{i,2});
end
end
end
function updateDatabase
%# updates the database
%# check whether there is already a comment
if size(database,1) > 0 && any(strcmp(name,database(:,1)))
idx = strcmp(name,database(:,1));
comment = database(idx,2);
else
idx = size(database,1)+1;
comment = {''};
end
%# ask for new/updated comment
comment = inputdlg(sprintf('please enter comment for %s',name),'add comment',...
5,comment);
if ~isempty(comment)
database{idx,1} = name;
database(idx,2) = comment;
end
end
end
Always always always keep the Matlab editor open with a script documenting what you do. That is, variable assignments and calculations.
Only exceptions are very short sessions where you want to experiment. Once you have something -- add it to the file (It's also easier to cut and paste when you can see your entire history).
This way you can always start over. Just clear all and rerun the script. You never have random temporaries floating around in your workspace.
Eventually, when you are finished, you will also have something that is close to 'deliverable'.
Have you thought of using structures (or cells, although structures would require extra memory use)?
'>> dataset1.numerical=5;
'>> dataset1.comment='This is the dataset that contains 5';
dataset1 =
numerical: 5
comment: 'This is the dataset that contains 5'
Related
I'm fairly certain after years of searching that this is not possible, but I'll ask anyway.
The question is whether it's possible to use a dynamic variable in an operation when you don't know the field name. For example, I have a data structure that contains a few hundred fields. The operator selects one of those fields and the program needs to know what data resides in the field from the data structure passed. So we'll say that there are 100 fields, and field50 is what the operator chose to operate on. The program would be passed in the field name (i.e. field50) in the FLDNAM variable. The program would read something like this the normal way:
/free
if field50 = 'XXX'
// do something
endif;
/end-free
The problem is that I would have to code this 100 times for every operation. For example:
/free
if fldnam = 'field1';
// do something
elseif fldnam = 'field2';
// do something
..
elseif fldnam = 'field50';
// do something
endif;
Is there any possible way of performing an operation on a field not yet known? (i.e. IF FLDNAM(pointer data) = 'XXX' then do something)
If the data structure is externally-described and you know what file it comes from, you could use the QUSLFLD API to find out the offset, length, and type of the field in the data structure, and then use substring to get the data and then use other calculations to get the value, depending on the data type.
Simple answer, no.
RPG's simply not designed for that. Few languages are.
You may want to look at scripting languages. Perl for instance, can evaluate on the fly. REXX, which comes installed on the IBM i, has an INTERPRET keyword.
REXX Reference manual
I apologize if this has been asked before (I couldn't find anything).
I'm an extreme noob in Livecode, and I want to know if there is a way of programming a button to create many new, unique variables and assign a value to them. I apologize if this is a dumb question.
Usually you use an array for that. An array is basically a list of things, where each thing is associated with an "index". An index can be any word, so you can use an array like a dictionary, where you'd e.g. have French words as the index, and English words as the value, like:
put "cow" into myDictionary["vache"]
But you can also just use numbers as the keys and make them a numbered list:
put "cow" into allMyAnimals[1]
put "duck" into allMyAnimals[2]
In end effect, you create one variable and put several things in it. For example if you had a loop that calculated something (in this example a number +100) and you wanted to have variables containing all those numbers, but named with 100 less, you'd do something like:
repeat with x = 1 to 250
put x +100 into twoHundredFiftyNumbersFrom101[x]
end repeat
And to read the first one:
answer "the first number is" && twoHundredFiftyNumbersFrom101[1]
Or all of them:
repeat with x = 1 to 250
answer twoHundredFiftyNumbersFrom101[x]
end repeat
Or whatever. You could also use 'do' to build the lines of code as a string, but then you have to make sure your variable names are generated in a fashion that makes them valid identifiers (e.g. have no spaces in them, no special characters). An array key can be any valid string, and the compiler can optimize them, and you can treat them as a whole and pass them between handlers.
Or you can do this "in the clear" with a "do" construction:
on mouseUp
repeat with y = 1 to 10
get random(100)
do "put it into onTheFlyVariable" & y
end repeat
end mouseUp
Step through this handler and watch the variables assemble themselves.
I'm hoping someone can help answer my question, perhaps with an idea of where to go or whether what I'm trying to do is not possible with the way I want to do it.
I've been asked to write a set of rules based on the data held by our ERP form components or variables.
Unfortunately, these components and variables cannot be accessed or used outside of the ERP, so I can't use SQL to query the values and then build some kind of SQL query.
They'd like the ability to put statements like these:
C(MyComponentName) = C(MyOtherComponentName)
V(MyVariableName) > 16
(C(MyComponentName) = "") AND V(MyVariableName) <> "")
((C(MyComponentName) = "") OR C(MyOtherComponentName) = "") AND V(MyVariableName) <> "")
This should be turned into some kind of query which gets the value of MyComponentName and MyOtherComponentName and (in this case) compares them for equality.
They don't necessarily want to just compare for equality, but to be able to determine whether a component / variable value is greaterthan or lessthan etc.
Basically it's a free-form statement that gets converted into something similar to an IF statement.
I've tried this:
Sub TestCondition()
Dim Condition as string = String.Format("{0} = {1}", _
Component("MyComponent").Value, Component("MyOtherComponent").Value)
If (Condition) Then
' Do Something
Else
' Do Something Else
End If
End Sub
Obviously, this does not work and I honestly didn't think it would be so simple.
Ignoring the fact that I'd have to parse the line, extract the required operators, the values from components or variables (denoted by a C or V) - how can I do this?
I've looked at Expression Trees but these were confusing, especially as I'd never heard of them, let alone used them. (Is it possible to create an expression tree for dynamic if statements? - This link provided some detail on expression trees in C#)
I know an easier way to solve this might be to simply populate the form with a multitude of drop-down lists, so users pick what they want from lists or fill in a text box for a specific search criteria.
This wouldn't be a simple matter as the ERP doesn't allow you to dynamically create controls on its forms. You have to drag each component manually and would be next to useless as we'd potentially want at least 1 rule for every form we have (100+).
I'm either looking for someone to say you cannot do this the way you want to do it (with a suitable reason or suggestion as to how I could do it) that I can take to my manager or some hints, perhaps a link or 2 pointing me in the right direction.
If (Condition) Then
This is not possible. There is no way to treat data stored in a string as code. While the above statement is valid, it won't and can't function the way you want it to. Instead, Condition will be evaluated as what it is: a string. (Anything that doesn't boil down to 0 is treated as True; see this question.)
What you are attempting borders on allowing the user to type code dynamically to get a result. I won't say this is impossible per se in VB.Net, but it is incredibly ambitious.
Instead, I would suggest clearly defining what your application can and can't do. Enumerate the operators your code will allow and build code to support each directly. For example:
Public Function TestCondition(value1 As Object, value2 As Object, op as string) As Boolean
Select Case op
Case "="
Return value1 = value2
Case "<"
Return value1 < value2
Case ">"
Return value1 > value2
Case Else
'Error handling
End Select
End Function
Obviously you would need to tailor the above to the types of variables you will be handling and your other specific needs, but this approach should give you a workable solution.
For my particular requirements, using the NCalc library has enabled me to do most of what I was looking to do. Easy to work with and the documentation is quite extensive - lots of examples too.
I'm using GameMaker:Studio Pro and trying to execute a script stored in a variable as below:
script = close_dialog;
script_execute(script);
It doesn't work. It's obviously looking for a script named "script". Anyone know how I can accomplish this?
This question's quite old now, but in case anyone else ends up here via google (as I did), here's something I found that worked quite well and avoids the need for any extra data structures as reference:
scriptToCall = asset_get_index(scr_scriptName);
script_execute(scriptToCall);
The first line here creates the variable scriptToCall and then assigns to it Game Maker's internal ID number for the script you want to call. This allows script_execute to correctly find the script from the ID, which doesn't work if you try to pass it a string containing the script name.
I'm using this to define which scripts should be called in a particular situation from an included txt file, hence the need to convert a string into an addressable script ID!
You seem to have some confusion over how Game Maker works, so I will try to address this before I get around to the actual question.
GML is a rather simple-minded beast, it only knows two data types: strings and numbers. Everything else (objects, sprites, scripts, data structures, instances and so on) is represented with a number in your GML code.
For example, you might have an object called "Player" which has all kinds of fancy events, but to the code Player is just a constant number which you can (e.g.) print out with show_message(string(Player));
Now, the function script_execute(script) takes as argument the ID of the script that should be executed. That ID is just a normal number. script_execute will find the script with that ID in some internal table and then run the script.
In other words, instead of calling script_execute(close_dialog) you could just as well call script_execute(14) if you happened to know that the ID of close_dialog is 14 (although that is bad practice, since it make the code difficult to understand and brittle against ID changes).
Now it should be obvious that assigning the numeric value of close_dialog to a variable first and then calling script_execute on that variable is perfectly OK. In the end, script_execute only cares about the number that is passed, not about the name of the variable that this number comes from.
If you are thinking ahead a bit, you might wonder whether you need script_execute at all then, or if you could instead just do this:
script = close_dialog;
script();
In my opinion, it would be perfectly fine to allow this in the language, but it does not work - the function call operator actually does care about the name of the thing you try to call.
Now with that background out of the way, on to your actual question. If close_dialog is actually a script, your suggested code will work fine. If it is an extension function (or a built-in function -- I don't own Studio so what do I know) then it does not actually have an ID, and you can't call it with script_execute. In fact, you can't even assign close_dialog to a variable then because it does not have any value in GML -- all you can do with it then is call it. To work around this though, you could create a script (say, close_dialog_script which only calls close_dialog, which you can then use just as above.
Edit: Since it does not seem to work anyway, check whether you have a different resource by the name of close_dialog (perhaps a button sprite). This kind of conflict could mean that close_dialog gives you the ID of the sprite, not of the script, while calling the script directly would still work.
After much discussion on the forums, I ended up going with this method.
I wrote a script called script_id()
var sid;
sid = 6; //6 = scriptnotfound script :)
switch (argument0) {
case "load_room":
sid = 0;
break;
case "show_dialog":
sid = 1;
break;
case "close_dialog":
sid = 3;
break;
case "scrExample":
sid = 4;
break;
}
return sid;
So now I can call script_execute(script_id("close_dialog"));
I hate it, but it's better than keeping a spreadsheet... in my opinion.
There's also another way, with execute_string();
Should look like this:
execute_string(string(scriptName) + "();");
I want to update a custom user field in QC using the Label of field instead of the name
At the moment we are doing it this way
Set currentRun = QCUtil.CurrentRun
currentRun.Field("RN_USER_03") = 1
currentRun.Post
But I would like to do it this way
Set currentRun = QCUtil.CurrentRun
currentRun.Field("Data Rows Passed") = 4
currentRun.Post
But I can't find the method to do it with.
Any Ideas?
Implying all labels are unique (which I doubt..):
You could create a function which accepts a label, searches in QC's tables that define customized fields for the correct field definition, and returns the field name. Then use the function's result value as the indexed property's index.
Suppose that function would be called "GetNameOfLabel", then the Caller's code would look like:
Set currentRun = QCUtil.CurrentRun
currentRun.Field(GetNameOfLabel ("Data Rows Passed")) = 1
currentRun.Post
Of course, the function would not really be trivial, but easy enough after some digging in the QC data model and finding an efficient way to fetch the name from the DB via SQL.
Or, the function could look up the name in an array, or a dictionary, then you would have to maintain that dictionary, but you would not have to go to the database for each lookup.
Disadventages:
Scripts with the wrong label might be harder to be debug
If labels are not unique, it might be real "fun" to debug
If looking up on the DB:
All scripts slow down if you don't cache, or pre-load, SQL query results for those lookups;
complexity, as you have to do the right SQL query, and you depend on QC's data model in a quite peculiar way (usually a horror when you're upgrading)
If looking up in an array, or dictionary:
You either must maintain its initialization (bet other admin guys adding a cust field will forget that easily), or must "load" it from QC's table (which is a bit like the SQL solution above, and has the same downsides).
I'd go with the array/dictionary-initialized-from-db-idea. Or, if you can live with the constant idea already presented, that one is a good bet. Considering that there is no session-independent scope in QCs customizing scripts, the SQL access idea might really kill performance because it would have to be executed for every new user session. Which is why I, too, +1'd the constant idea.
Look at this:
Dim gFieldLabelToNameDICT: Set gFieldLabelToNameDICT = CreateObject("Scripting.Dictionary")
gFieldLabelToNameDICT.CompareMode = vbTextCompare
Function GetNameOfLabel (strFieldLabel)
' If it doesn't exist yet in fieldLabelToName dict -> search it using TDC and add it to the list to improve performance
If Not gFieldLabelToNameDICT.Exists(strFieldLabel) Then
Dim testSetFields As List
Dim testSetFields: Set testSetFields = QCUtil.QCConnection.Customization.Fields.Fields("RUN")
For Each aField in testSetFields
If aField.UserLabel = strFieldLabel Then
gFieldLabelToNameDICT.Item(strFieldLabel) = aField.ColumnName
End If
Next aField
End If
GetNameOfLabel = gFieldLabelToNameDICT.Item(strFieldLabel)
End Function
Maybe you shall want to add some more error handling, such us considering the case that the label is not found.