24 questions linked to/from Levels: how do they work?
144 views

Indicate level with Replace [duplicate]

Replace[{{x^2, Sqrt[x]}, {x + 1, x - 3}}, f_[x__] -> f, 1] Level 1 of Replace works here as expected with output {List,List} ...
• 2,311
44 views

Understand the notion of level with apply [duplicate]

There is something I don't understand with the notion of levels with apply. I take this example : Apply[f, {{a, b, c}, {d, e}}, {2}] Mathematica answers me : <...
• 2,164
156k views

Where can I find examples of good Mathematica programming practice?

I consider myself a pretty good Mathematica programmer, but I'm always looking out for ways to either improve my way of doing things in Mathematica, or to see if there's something nifty that I haven't ...
106k views

Assign the results from a Solve to variable(s)

I understand Mathematica can't assign the results of a Solve to the unknowns because there may be more than 1 solution. How can I assign the 4 values of following result to variables? ...
• 6,856
3k views

how to efficiently apply function to all pairs of a set (and collect the results)

To build a graph, I need to apply a function f[a_, b_] to all pairs of a list (3500 elements). The function itself returns a link ...
• 353
613 views

ReplaceRepeated seemingly omits some rules

Is there a simple way in Mathematica to prevent rule reordering? Let me give an example: ...
930 views

How to Apply Functions to Lists with Many Curly Brackets?

For example, consider the list defined below. samplelist = {{{1,2,3,4}}, {{5,6,7,8}}}; How would I apply the Times operator ...
• 505
676 views

Extract all Values from nested Association

Considering we have an Association: ...
• 2,765
2k views

Creating a third list from two given lists [duplicate]

I imported 2 lists of the form {{x1,y1}, {x2,y2}, ...} and {{x1,y'1}, {x2,y'2}, ...} into Mathematica. I want to make a ...
• 41
353 views

Position with test for list of lists [duplicate]

Why do I get this error message? It seems to me that the level specification should have done the job. ...
• 1,610
353 views

Mapping on leaves

Say I have some nested structure, such as {a,{{b,c},d,{e,{f,g}}}}, and I want to apply a function $q$ to each of the leaves; that is, I want the output to be ...
• 4,209
1k views

Use map on a different level

I have just started to get used to Mathematica's Map, Apply, and related functions, and I can't figure out how to do maps that require working "one level down". For example, I am currently trying to ...
• 1,030
1 vote
376 views

Extract all elements from a list that belong to a set or have a set element as an argument

EDIT: Added that I want to extract not only the variables from a specific set, but also functions involving variables from a specific set. Given the set ...
• 21
1k views

What do brackets around a levelspec option do?

The following code returns the first three integer elements of Sqrt[Range[100]]: ...
• 1,461
367 views

Is there a way to use Table[] without having to calculate my function twice?

I'm trying to use Table[] more to be more in the spirit of Mathematica. So for example, I might replace this piece of code: ...
• 775
214 views

why Level does not sort output according to their levels

Consider this example: Level[a + f[x, y^n], {0, Infinity}] (*{a, x, y, n, y^n, f[x, y^n], a + f[x, y^n]}*) Why the output is sorted in this way. why not ...
• 19.9k
240 views

Why Cases and Select treat the List differently?

Look at these two examples: In[1]:=Select[f[i], MatchQ[_f]] Out[1]:=f[] In[2]:=Cases[f[i],_f] Out[2]:={} It seems that the Select take $f[i]$ as List, but Cases ...
• 397
277 views

Levels and slots

I am struggling with levels and #, if I understand this I think I will be able to grasp the entire concept. ...
• 1,219
241 views

Levelspec range with negative levelspec

Documentation states A negative level -n consists of all parts of expr with depth n. However, it is not clear what do level ...
• 1,530
151 views

What exactly do single brackets represent syntactically?

I'm trying to deepen my understanding of the mathematica language after having messed around with it for a long time. I'm reading the book "mathematica programming Intro". Unfortunately, I don't ...
• 545
82 views

Higher functional programming partial substitution

This h[g_, x_] := g[x] h[Sqrt, x^2] works obviously as well as : f[x_]:= x^2 h[f,x] but if ...
• 4,582
1 vote
68 views

How to use syntax instead of double for loop

I would like to find the distance between a point list (i.e dalist) and list of centers (i.e framecenters). I used the following ...
• 501
1 vote
60 views

Head of level : question about the Apply function

I am not sure to really understand how the function Apply works at level 2 for example. I have read this question and few others and it doesn't help me :Levels: how do they work? Take the following ...
• 2,164
62 views

Where can I find mathematica documentation about @@@? [duplicate]

For example, to build a rule from 2 lists {a,b,c}, {1,2,3}, I use: ...
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