Questions tagged [data-types]
Mathematica pseudo-types Integer, Real, Rational, Complex, String and Symbol, and their use.
49
questions
3
votes
1answer
38 views
Type formation rules for 1-position expressions
I made a summary of the rules for formation of types for simple 1-position expressions, as I understand them.
Here it is in textual form:
A symbol, say, α, is a discrete entity, represented by a ...
7
votes
1answer
179 views
Using DataStructures in FunctionCompile
This is a follow up to this StackExchange question
I am trying to do the equivalent of Select on a "FixedArray" data structure.
Here is what I have tried so far:
...
1
vote
0answers
48 views
“Compile-time” patterns
If I define a function like
f[x : {_, _Integer}] := (* function body *)
then, as I understand it, every time f[expr] is ...
2
votes
0answers
81 views
How to use _Complex types in CUDAFunctionLoad?
The documentation for CUDAFunctionLoad specifies various base datatypes you can use for your function's arguments, including ...
1
vote
1answer
94 views
Adding a curve on DensityPlot: Epilog -> First[ContourPlot[…]] why the first?
I would like to understand why I have to add First around ContourPlot in the following example to have it working:
...
1
vote
0answers
40 views
How to use TypeFramework?
I found a paclet "TypeFramework". It seems to be designed for typed programming. How can I use it?
3
votes
1answer
230 views
How to use patterns to specify variable type as Boolean (True, False) in analogy to x_Integer, x_Real, x_Complex, x_List, etc
Say I define a function f[x_, y_]:= ..., the concrete definition of which is not important now.
What is important though is, that I want ...
1
vote
0answers
96 views
How to restrict the type of input given to the function Input[]?
The function Input[] when evaluated displays a dialog box where one can enter any character. My question is how do I restrict the input only to a certain type such ...
6
votes
1answer
289 views
Provide definition to FunctionCompile
I recently upgraded to Mathematica 12, and I've been excited to explore new features such as FunctionCompile, which produces llvm code.
I tried compiling the ...
1
vote
0answers
43 views
SemanticImport changes “string” type to “quantity” type--how to change during import or after import?
This question may overlap with other questions about the quirks of SemanticImport, but I don't see this specific wrinkle on StackExchange and I hope it will be a simple answer to help me and others ...
7
votes
1answer
159 views
What is an example of of idiomatic “typed” WolframScript?
I'd like to make my own "typed function" in WolframScript. Suppose the type we desire is called money, and we'd like to make a function called ...
10
votes
2answers
606 views
Make symbols atomic, without losing their type
So, I'd like to define a matrix M, that does not decompose into it's constituents when I do things like Tr[M], but I also want it's type to be retained.
(By type, ...
0
votes
0answers
180 views
CompiledFunction::ctfa - Argument should be a rank 4 tensor of machine-size real number
Dear Mathematica community,
I got the following error line:
CompiledFunction::ctfa "Argument {<<1>>} at position 1 should be a rank 4 tensor of machine-size real number"
This ...
0
votes
1answer
51 views
Who knows what happened in this code? (The difference between 3 and 3.)
I have a problem in my code. This code produces two different results when we use GM = {{Sqrt[3.], 0}, {-Sqrt[3], 3}/2} and GM = {{Sqrt[3], 0}, {-Sqrt[3], 3}/2}, where I just use Sqrt[3] instead of ...
20
votes
1answer
419 views
NumericArray versus PackedArray in MMA12
I just tried to understand the differences between NumericArray and PackedArray in MMA12. The memory footprint of a ...
10
votes
1answer
269 views
Is it possible to restrict the arguments for a function to a specific entity type?
I'm trying to wrap my head around how to work with Mathematica for building (computable) domain specific knowledge. One particular thing I didn't quite understand is how to create symbols for ...
23
votes
2answers
2k views
Why no RationalQ or RealQ?
Interesting pattern came up as I go through the homework replies of my students. Why is there no RationalQ or RealQ? We have <...
2
votes
1answer
54 views
Data Type that can contain multiple data types
In MATLAB one can use cell arrays and structures to "hold" data of different types. For example, one can define a cell array in which the first cell contains an array, the second a differently sized ...
4
votes
1answer
759 views
How to convert entity to string?
I have an entity city. For example, I run {city} = GeoNearest["City", GeoPosition[{41.8, -87.7}]] and then I got The entity "...
13
votes
1answer
218 views
Is it possible to set multiple type to a variable?
Consider this
f[x_Real] := 2 x
f[1]
f[1]
f[1.0]
2.0
I want ...
1
vote
2answers
116 views
How to create an unevaluated command like Sequence
I work with linear combinations of graphs,
$$c_1 G_1 + c_2 G_2 + \dotsc,$$
and I want to represent them in my Mathematica code. I represent graphs as adjacency matrices, e.g.
...
3
votes
1answer
171 views
How to define “typed” objects and their operator specializations?
I've defined a primitive sort of type system where my objects are defined as lists with an associated identifier:
...
1
vote
0answers
42 views
Integer data type mapping problem with SQLInsert in DatabaseLink package
I am working with a following SQL table named "ticket". Now let's see the data types for the columns.
...
4
votes
1answer
228 views
Specify Variable Size
Is there an easy way to specify the variable size and still use them as variables more specifically for the .NETLink?
Something like the following I am thinking.
...
1
vote
1answer
125 views
Control data type (or precison?) to limit memory usage
I couldn't find the answer to my question, so here it is:
I have quite a large table, which I generate in Matlab (for some reasons i use both Matlab and Mathematica, I'd like to use only one of them, ...
8
votes
2answers
14k views
How to get the type of an object
I'm looking for a way to get the type of an object:
TypeOf["x"] -> String
TypeOf[1] -> Integer
Or something along those lines.
5
votes
1answer
376 views
Immutability, Association and typing
I have read the article by Leonid on the question. I am still struggling.
I am trying to use Association to inject some pseudo-typing in my code.
Here is my ...
1
vote
0answers
168 views
Compilation error: “Could not complete external evaluation at…”
I'm pretty new to trying to use Compile[], and I just can't see why I'm getting this error.
I have two functions to define beforehand; one of them is a bit odd:
<...
18
votes
0answers
270 views
V10's TypeSystem - what are these function useful for? [closed]
The symbols in the TypeSystem` context are clearly used for working with Datasets, but they seem powerful. I was hoping that someone could help explain how they work and is they are useful for ...
1
vote
0answers
64 views
Pattern type and list indexing warnings/errors
I'm new to Mathematica and am trying to implement some simple noise functions in it in hopes of eventually finding an integral for them. This is the interesting part of the code:
...
4
votes
2answers
75 views
Type error before replacement rule is applied
When I type
a <> "0" /. {a -> "1"}
I get the error
...
13
votes
1answer
4k views
How to convert a column of a Dataset into a list [closed]
I'm loving the fact that Mathematica has finally implemented the Dataset feature, but I'm still struggling a little with it. I have a Dataset that contains a bunch of functions for different diseases ...
3
votes
1answer
250 views
Datatypes and numbers in Mathematica
I have some questions about numbers in Mathematica:
Does Mathematica work with datatypes like int, long, ...
4
votes
1answer
50 views
Relative factorisation with scalar quantities
I'd like to find a natural way to tell mathematica that a given unknown in a polynomial should be treated as a number, unlike the other variables.
Typically I'd like to sum two polynomials in several ...
2
votes
1answer
89 views
Type declaration for list arguments
How can I make
f[n_Integer]=2*n
valid for a list of integers? For example:
f[nlist_Integer] := 2*nlist[[1]]
does not work ...
1
vote
0answers
78 views
How can I perfect this game for Wolfram Demonstration publication? [closed]
When the messages change the window inactivates, and when I try to host an interactive CDF on my site it turns red and says something about numbers having to be scaled or offset. Any help?
I'm ...
2
votes
1answer
526 views
Declare type in InputField
Is it possible to declare a type in InputFunction to only accept positive Integers as input?
I know i can create an ...
13
votes
1answer
12k views
Get expression type?
Is there a built in function that distinguishes between different kinds of variables?
I mean something like:
VariableType[ 123 ]
Number
...
5
votes
1answer
146 views
Determine return type of CompiledFunction expression
Is there a way to extract the types of the arguments and the return type from a CompiledFunction expression? I am writing a package for code generation (basically a wrapper around CCodeGenerate) where ...
12
votes
3answers
352 views
Find all heads a function is defined on
So say I've got a function g defined as follows:
g[x_Integer] := x + 1
g[s_String] := s <> "!!!"
How would I write a ...
4
votes
1answer
257 views
Using less memory to store and manipulate specific types
Is there a simple way to use Integer types (in particular, a table of Integer types) that require only 4 or 8 bytes (reps. 32 and 64 bits) representation?
It seems that integers in Mathematica have a ...
6
votes
1answer
142 views
Behavior of 1.2 ∈ Rationals changes in v9?
A friend of mine using version 9 recently showed me this:
It's strange because in version 8.0.4 1.2 ∈ Rationals does return ...
3
votes
1answer
131 views
.NET link - index of property
I have a property in .NET Type, which is actually a generic list of objects. When I try access the property using numeric index e.g. 10, this works. However when I iterate through indices using ...
1
vote
1answer
809 views
Mathematica command for type checking?
I have a program where users can enter mathematica commands that can evaluate to any of the standard numeric types (complex, real, int, etc.), or to boolean values. Moreover the users can enter ...
27
votes
6answers
12k views
How to check if an expression is a real-valued number
What is a simple, fast way to test whether an expression is a real-valued number? I ask since there is no RealQ function.
If we call this test ...
2
votes
3answers
826 views
What format to use to store expressions in database?
I am storing lists of expressions into a MySQL database. Each list is of form
{_String, {_String, _Real}, _Real}
What data format should each column of the ...
38
votes
4answers
4k views
How to create strong types?
In a program I'm writing, I create a list of lists, that looks something like this:
{{100, {1,2,3,4,5}},
{105, {2,4,6,8}},
{42, {42,39,56}}}
I then pass this ...
118
votes
7answers
16k views
Struct equivalent in Mathematica?
I really miss having something like a struct in Mathematica. I know of (and regularly use) a couple of programming techniques which feel like a ...
7
votes
3answers
350 views
Does there exist any way to add type annotations?
Is there any way to add my own annotations to values or functions in Mathematica? Imagine, for example, that I wanted to annotate a List specifically as a ...
