I created a string Path="E:\" to assign a value to a variable with Eval. But it returned a run-time error 2766: This object cannot contain 'automatic' object 'Path'.
Is there a way that I can work on variables with string? I have strings of variables and strings of values. This would save me lot of time.
Many thanks
You can't use Eval to set a variable within the expression. If you write it like this:
Path = Calcu.Eval("E:\tables")
you'll get the answer in the Path variable. Obviously, this is the same as
Path = "E:\tables"
but that is a different topic. If you want the variable name to be dynamic as well, then you are probably doing something wrong. If you really want it, the you need to have a look at VBIDE.VBProject, but don't go there until you have a fairly good understanding of VBA.
Related
Is there a way in Java to have text file with listed a=10.35 b=20.57 c=30.79 and get program to only read the variable decimal values and assign them to declared variables a, b, c in the program.
Searched youtube found nothing.
Do not know if it is possible.
Do not know.
Got it working.
You can certainly read in the contents of the text file and parse it down to the chars and doubles.
If you are referring to declaring named variables based on the file, there is no way to do this directly at runtime. You can, however, use a data structure like a dictionary or map to store the data and access it using the name as a key.
If you could provide more details about what you are trying to do, that would make it easier to answer your question more specifically.
A program variable is an abstraction of a computer memory cell or collection
of cells. Programmers often think of variable names as names for memory locations, but there is much more to a variable than just a name.
In this case, what is an anonymous variable?
What does the below statement mean?
Variables without names are called anonymous variables.
Can you provide language specific examples for the same?
In C++, reference variable to const can be initialized by constant.
In this point, temporary variable is created in memory to grab the constant.
const int &ref = 3;
like this. so we can call this temporary variable to "anonymous variable".
Variables are where you store you values. 'Variable Name' is the usually the easiest (and more human-like) way to locate your value.For example, if I am a variable, you can get my value by calling my name, and the combination of my value and my name is called 'variable'.
However, not all variables need a name.Sometimes you just use them once and don't need them anymore; and in that case, a name is unnecessary.
The example given by #BAE HA RAM is a telling one,in which case you don't need a name for the value but ref to it by a pointer(But still got a name for that pointer)..
There are also many other anonymous things, anonymous type, anonymous function and so on. Most of them are created to avoid too many meaningless names for the things that you only need to run once.
I'd like to know which language you are using, so more specific example can be given...
Is it possible, in ABAP, to evaluate string templates dynamically?
Normally, you will have some string template in code that will be checked by the compiler. (The variables in the curly brackets are checked by the compiler at compile time).
However, is it possible to have a string evaluated at runtime?
So, instead of:
data(val) = |System ID: { sy-sysid }|.
I would like the string to be interpolated to come from elsewhere, for example:
parameter: p_file type string lower case default '/mnt/{ sy-sysid }/file.txt'.
In this case, I would like to have the value of p_file to be evaluated at runtime to substitute the variable (sy-sysid) with the runtime value.
You could, of course, program your own substitution by finding all occurrences of variables with curly brackets with a regex expression, then evaluate the variable values with ASSIGN and substitute them back into the string, but I am looking for a built-in way to do this.
Sorry, this is maybe a stupid example, but hopefully you understand what I mean. (If not, please let me know in the comments and I will try and clarify).
The problem in your snippet is not with string template but with PARAMETER behavior. It does not allow dynamics in DEFAULT clause.
To achieve what you want you should use INITIALIZATION and set path value in runtime:
parameter: p_file type string lower case.
INITIALIZATION.
p_file = | /mnt/{ sy-sysid }/file.txt |.
Unfortunately, the example you gave, does not make any sense to me. ABAP String templates are evaluated at run-time and type-checked at compile-time.
In your example, it is always the run-time value of SY-SYSID that will be written to the variable.
I guess what you want to do is circumvent compile-time checks for expressions inside a string template.
Please try to give us your actual use case, so maybe we find an even better solution to your problem.
However, here is what I think could help you:
Personally, I do not recommend to write code like the one below, because it is extremely error-prone likely to mislead other programmers and because there is very likely a better solution.
Given that you know the name of a variable at run-time, try this:
".. say LV_VARNAME is a charlike variable that contains a
" variable name at runtime.
"NOTE that the variable LV_VARNAME must be visible in the scope of the
"following code.
FIELD-SYMBOLS: <my_var> TYPE any.
ASSIGN (lv_varname) TO <my_var>.
DATA(lv_str) = |The value is { <my_var> }|.
i'd like to know if there is any possibility to read out dynamic variable names?
Since the programm that passes the variables to my script calls them just "in1, in2, in3" etc.
Hopefully there is any way to make a loop, because it is pretty annoying to handle every input separately...
Here is what i've tried so far, but it just gives me an error.
for i=1,19,2 do
myvar[i] = ["in"..i]
end
I'm quite new to Lua, but i hope the solution is not that difficult :D
Edit:
Oh I'll try to give you some more information. The "Main" Program is no not written in Lua and just set theese "in1 ... " variables. It is a kind of robotic programmic software and has a lot of funktions build in. Thats the whole thing so i can not simply use other variable names or an array. So it is not a function or anything else related to Lua...
Here is a little Screenshot http://www.bilderload.com/daten/unbenanntFAQET.jpg
At the moment the Lua script just passes the the first input.
It depends on what you mean by "dynamic variable names."
The names of local variables do not exist. Local variables are any variable declared as a function parameter or with the local keyword. Local variables are compiled into offsets into the Lua stack, so their names don't exist. You can't index something by name to get them.
Global variables are members of the global table. Therefore, these ways to set a global variable are equivalent:
globalVar = 4
_G.globalVar = 4
_G["globalVar"] = 4
Since the programm that passes the variables to my script calls them just "in1, in2, in3" etc.
The program that passes variables to your script doesn't get to name them. A variable is just a placeholder for a value. It has no ownership of that value. When your function gets arguments, your function gets to name them.
You haven't said much about the structure of your program, so I can't really give good advice. But if you just want to take some number of values as parameters and access them as inputs, you can do that in two ways. You can take a table containing values as a parameter, or you can take a varargs:
function MyFunc1(theArgs)
for i, arg in ipairs(theArgs) do
--Do something with arg.
end
end
function MyFunc2(...)
for i, arg in ipairs({...}) do
--Do something with arg.
end
end
MyFunc1 {2, 44, 22} --Can be called with no () because it takes a single value as an expression. The table.
MyFunc2(2, 44, 22)
Whoever wrote the code that spits out these "dynamic variables" didn't do a good job. Having them is a bad habit, and might result in data loss, cluttering of the global name space, ...
If you can change it, it'd be much better to just output a table containing the results.
That said, you're not to far off with your solution, but ["in"..i] is no valid Lua syntax. You're indexing into nothing. If those variables are globals, your code should read:
for i=1,19,2 do
myvar[i] = _G["in"..i]
end
This reads the values contained by your variables out of the global table.
Try this
myvar={ in1, in2, in3, in4, in5, in6, in7, in8, in9, in10, in11,
in12, in13, in14, in15, in16, in17, in18, in19 }
if the variables are passed as global variables, or this
myvar = {...}
if the variables are passed as arguments to the script.
In VBA, I want to use a name for a local variable that I'd also like to use for a function name. The problem I'd that the function name formatting always changes to the local variable formatting.
Any way to prevent that?
I highly recommend not using the same name for disambiguation purposes. Also, if VBA is not case sensitive, it may not know whether you are referring to the function or the variable and thus give a runtime error (I don't think it is compiled per se, but it goes to a proprietary p-code intermediate.)
Often when you'd like the names to be similar, it can be useful to prepend an underscore to one, such as a local variable. Thus I recommend you name the function FunctionName and the variable _FunctionName if you want to go that route.
If you want to try having the same name for each, you will likely need to edit the code outside of the IDE that is reformatting your code. In an editor that doesn't try to auto-format, you may be able to force it. Then whether it compiles or not is the question.
In Visual Basic, each function already has a variable named after the function. Assigning a value to this variable is the only way to set a return value for this function.
Therefore, declaring yet another variable of the same name creates ambiguity. You cannot do so. It results in the Duplicate declaration in current scope error.
And if by "local" variable you meant a module-level variable, then you cannot do it either: Ambiguous name detected: %s.
And if you are asking about a situation when a function and a variable of the same name belong to different scopes, then VBA will use the case of the line that was edited last. So if you declare a function and then declare a variable in another module, the function name will change case. But if you then return to the function, change its casing back and press Enter, the variable, in its turn, will change its casing to match the function name.