Questions tagged [map]
Questions about applying functions or operators to expressions, especially constructs that take advantage of Map (/@) functionality.
378
questions
3
votes
2
answers
43
views
Apply function to specific elements in list [closed]
Say I have a list like myData={{1,m1,v1},{2,m2,v2},{3,m3,v3},{4,m4,v4}}. It could be a dataset, where the first and second variables in each tuple is as desired, ...
- 123
4
votes
5
answers
177
views
Converting specific positions of a List into Sublist
Suppose I have a List of numbers:
num = Range[5]
I want to combine the second and the third element into a sublist to get the result as {1,{2,3},4,5}.
I tried ...
- 585
5
votes
3
answers
122
views
Complicated double mapping over nested list
I have a list that each term consist of two parts. First part is a graph and second is a list of pairs of vertices that I want to find graph distance of.
...
- 3,840
4
votes
2
answers
201
views
What should mapping over a number or symbol produce?
I expected it to be an error (i.e., produce an error message), but Map[f,num] is num. Why is this the correct behavior? If it is ...
- 12.7k
11
votes
2
answers
449
views
How can I create an atomic head or treat some head as atomic during Map?
For example,
Map[g, {0, {h[1, 2, 3]}}, {-1}]
gives
{g[0], {h[g[1], g[2], g[3]]}}
I want a ...
- 16.4k
2
votes
2
answers
81
views
Mapping Part to a List [closed]
I have a list, x, where each member is itself a list of 2 coordinate points. Sometimes a member is a list of only 1 point, sometimes it is a list of more points. Note that the last member below is a ...
- 195
7
votes
3
answers
428
views
How do I map a function pairwise?
Given a list of pairs:
data = {{a,b},{c,d},{e,f},{g,h},{i,j}}
I need the moving map:
MapPair[F,data]
...
- 19k
5
votes
2
answers
409
views
Maps between finite sets
With SageMath, one can do FiniteSetMaps(["a", "b"], [3, 4, 5]) to get all maps from {a,b} to ...
- 335
14
votes
4
answers
632
views
Monitoring Apply / @@@ over large lists
How to monitor and/or print partial progress of Apply, e.g. f @@@ list?
I have found answers using Map (e.g. this nice trick using Echo, or this general trick), but ...
- 243
6
votes
5
answers
812
views
How can I apply a function only to even-index elements of a list?
A = {1, 2, 3, 4, 5}
and, Dd[P_] := P + 1
How can I map "Dd" into "A" such that the outcome is: {1, 3, 3, 5, ...
- 61
7
votes
5
answers
433
views
Smart way to remove rules from lists, leaving just values, specifically from FindMinimum output
I would like to know if there is a direct way to remove the rules from a list of rules.
I know that, simply, this can be done with:
...
- 561
4
votes
1
answer
77
views
Mathematica replaces list of zeros with zero [closed]
Consider the following functions:
f[x_]:= {{Im[x], Re[x]}, {Re[x], Im[x]}};
g[x_]:= {{Im[x],0},{0,0}}
When applying each of the functions to the list of lists <...
- 235
7
votes
1
answer
173
views
How can I do "Map" on a binary function?
If there is a one-variable function, we can f/@{a,b,c} to get {f[a],f[b],f[c]}
What to do with it if it comes to a binary ...
- 337
5
votes
1
answer
135
views
A Naive Prime Test Implementation - Problem with Table
I tried to write a simple function which implements a naive primality test.
...
- 153
5
votes
2
answers
330
views
Map a two argument function to every element on list
I'm new to use the amazing map function in Mathematica, and I've found it really elegant to program in simple lines of code. However, I'd like to perform more elegant stuff. I've found this question, ...
- 561
0
votes
0
answers
39
views
Trying to map SparseArray over a defined list, the SparseArray defined with 3 subvalues i want to map the 3rd. subValue(list) over the defined list
I have a SparseArray already defined as following
...
- 1
1
vote
1
answer
87
views
ReplacementAll with list elements
I'm trying to define a function that replaces certain expressions that appear when calculating scattering amplitudes (not important). Basically, I have a function ...
- 209
0
votes
1
answer
71
views
How to use map and slot effectively?
I want to change my code from :
f[n_, x_] := n Sin[x ]
Table[{x, f[0, x], f[1, x], f[2, x], f[3, x]}, {x, -\[Pi], \[Pi],1.0}] // Chop
with OUTPUT :
...
- 664
3
votes
0
answers
66
views
Video processing: Efficient way to apply function to pixel time stack (FIJI's Intensity Z-projection)
Starting from a Video, I would like to apply a function f to the stacks of intensity values, over time, for each pixel. In FIJI ...
- 31.2k
2
votes
4
answers
259
views
Applying f for a part of list (MapAt is slow)
Suppose that there are 2000 stones in a row.
You should grind 1000 of them to make beads.
The time loads(making beads) for each stone are similar.
But which 1000 stones?
case1) the first 1000 stones.
...
- 3,231
0
votes
1
answer
33
views
Private variable issue in a function environnement
I have the following matrix which represents an input from a .txt file. The first column gives the name of the random variable, the second the probability law, the third the parameters related to the ...
- 378
0
votes
2
answers
58
views
How to construct a function that picks elements of the kind $\{-1,\{\}\}$?
I am trying to do the following: Given the list {{-1,{}},{2,{1,2}},{-7,{}},{a,{}}}, I am trying to construct a function that throws out all elements with anything ...
- 4,911
0
votes
2
answers
51
views
How to apply a function to the elements of a list with the "L /. x_ ->f[x]" notation? [closed]
Suppose we have a list:
{5,6,7}
Suppose I have a function like GCD[x,10] and I want to apply it to the given list. I'm trying ...
- 4,911
1
vote
1
answer
47
views
How to separately pass elements of a 3D list as part of the arguments of a function
Hi I have a function which its arguments have the form F[a,b,c,d,e] but the 2nd to 4th arguments are in a list of the form R={{{b,c,d},{e,f,g}},{{h,i,j},{k,l,m}}} how can I pass these elements as ...
- 350
0
votes
1
answer
106
views
Contour plot with x, y and z values?
I have x , y and z as
x = List[1.355, 1.357, 1.359, 1.36, 1.357, 1.355];
and
...
- 175
0
votes
0
answers
52
views
Converting 1D map into first order differential equation for bifurcation diagram code
I have existing code to plot bifurcation diagram for coupled first order differential equations. It seems to work for coupled differential equations. To test the code further, I use the simplest ...
- 863
0
votes
0
answers
44
views
Trouble with bifurcation of differential equation
The code for bifurcation is written in such a way that it will allow plot bifurcation for any number of differential equation. Thus I am trying to avoid maps and iterations. Unfortunately it does ...
- 863
0
votes
0
answers
29
views
How to make a manipulatable map that can change color?
I want to color the world map differently according to how much the number of each country. For example, USA using renewable energy for 20% should be colored lighter than Canada using renewable for 50%...
0
votes
0
answers
28
views
Adaptation of existing code to multivariable system
I am trying to adapt the existing code from "Mathematica package for analysis and control of chaos in nonlinear system" by Gutierrez. This existing code calculates the Lyapunov Exponent by ...
- 863
1
vote
0
answers
62
views
How to find N most populous cities in each state with TakeLargest and Entity Functions without waiting forever using Caching?
I am interested in using Entity Functions such as EntityValue, FilteredEntityClass, EntityFunction, EntityClass, EntityList, and GeoEntities to help me find N most populous cities in each state. I ...
- 1,097
0
votes
1
answer
62
views
Mapping data from 2 files imported
I'm not in prog major. This course is needed as an elective for another major. Thus any help is appreciated.
DataA and DataB ...
- 1
5
votes
1
answer
264
views
1
vote
0
answers
88
views
compiled function not mapable
I am currently working on speeding up a larger project and thus using FunctionCompile. I have come across the issue that a manual input of list elements produces a valid results, however if I try to ...
2
votes
2
answers
120
views
How to split many controls in Manipulate into multiple columns (saw some potential bugs)
I need to use Manipulate[] with many controls, because I have around 40 parameters which I want to be able to alter. Since the number is too large, I want to split these controls into multiple columns,...
- 675
2
votes
0
answers
96
views
How to use Select and MemberQ together with Map correctly?
I have a list with quite a few elements. Each element is a rule of the type vector-> number such as {1,2,3,4}->1.435 and ...
1
vote
0
answers
92
views
Map a function that uses the lists indices as arguments
Suppose I have a function f[x_] that I want to Map over somelist (assumed to be one ...
- 45
1
vote
0
answers
170
views
How to limit the cpu usage of Mathematica?
I am runing mathematica with ParallelMap[], on a win10 computer with 8 physical cores.
The cpu usage always rocks up to 100%, though ...
- 57
0
votes
0
answers
85
views
Evaluate a function with 3 different variables for the whole list of each variable
I have a function with 3 variables
f[t1,t2,t3]
Each function has a list of values
...
2
votes
1
answer
90
views
Considerations for Compiling and Parallelizing Code Outside or Inside Map[]
Assume f as well as Map[f,list] are parallelizable and compilable, such that parallelization and compilation give significant ...
- 1,577
2
votes
2
answers
101
views
Mapping list elements without using Table function
How could I generate the following list of points using some function or mapping without using the table function.
...
- 111
3
votes
1
answer
74
views
How to Map over a BlankSequence? [closed]
I would like to replace any function f[x, y, ...] in a certain expression with the same function with all its arguments squared, i.e. ...
- 117
4
votes
3
answers
160
views
Curious about Mapping over multiple multiple arguments [closed]
To my shame, I have discovered the power of Map quite recently and since then I have been using it more and more. But increasingly I find myself trying to use ...
- 573
3
votes
0
answers
75
views
How to digitize a vector field?
Is there some way that I can digitize both the direction and the magnitude of a vector field accessible in JPEG format?
To clarify what I mean, I want to have the numerical value of: 1)magnitude and 2)...
4
votes
2
answers
81
views
Applying transformation rule for corresponding indices?
I have two lists, that looks like below
list1 = {a, x, b, x, x, c};
list2 = {2, 3, 4, 5, 6, 7};
Any time there is an x in the ...
- 747
0
votes
0
answers
112
views
Iteration limit exceeded
I am trying to adapt the following piece of code (coming from this answer):
...
- 6,214
1
vote
1
answer
95
views
how I should use `MovingMap` on a `Dataset`?
I am aware of How would I use Map on a Dataset column? still I cannot see how I should use MovingMap on a Dataset.
Even the ...
- 1,350
0
votes
1
answer
79
views
Recursive addition of vector list to last elements of vector lists
This question refers to an extension of Add list of vectors to list of vectors recursively . I tried hard to complete the problem but now I got stuck. I have vectors
...
- 2,030
5
votes
2
answers
139
views
bind specific 'Slots' to specific 'Map'
Is it possible to construct a pure function using multiple slots, with the following concept :
Binding specific slot to specific apply or map
For example :
In this example,
To ...
- 3,231
3
votes
2
answers
138
views
Restrict kinds of heads when dealing with level concept
In[1] Map[(# + 7) &, {a, 3 b, {c, d}, e}, {2}]
Out[1] {a, 10 (7 + b), {7 + c, 7 + d}, e}
But I want feature like ListMap :
...
- 3,231
0
votes
0
answers
44
views
calculate differences of a list using slots
I want to calculate the differences between the numbers of a list. One way to do that is using 'Differences'.
For example:
L = {1, 3, 6, 9};
Differences[L]
this ...
- 2,371