Questions tagged [data-types]
Mathematica pseudo-types Integer, Real, Rational, Complex, String and Symbol, and their use.
40
questions
1
vote
0answers
22 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
105 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
537 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
27 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 is my function:...
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 ...
15
votes
1answer
232 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
244 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 ...
22
votes
2answers
1k 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
42 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
269 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 "...
12
votes
1answer
165 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
83 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
132 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
38 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
217 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
106 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, ...
4
votes
2answers
6k 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
295 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
141 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:
<...
17
votes
0answers
200 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
61 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
73 views
Type error before replacement rule is applied
When I type
a <> "0" /. {a -> "1"}
I get the error
...
7
votes
1answer
2k 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
213 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
47 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
76 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
374 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
10k 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
118 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
308 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 ...
3
votes
1answer
216 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 ...
5
votes
1answer
138 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
118 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 ...
0
votes
1answer
714 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 ...
22
votes
6answers
9k 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
812 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 ...
37
votes
4answers
3k 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 ...
111
votes
7answers
14k 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 ...
6
votes
3answers
312 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 ...
