Linked Questions
24 questions linked to/from Levels: how do they work?
0
votes
0
answers
145
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}
...
- 2,341
0
votes
0
answers
47
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 :
<...
- 2,184
604
votes
19
answers
158k
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 ...
65
votes
10
answers
109k
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?
...
- 6,998
14
votes
3
answers
4k
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 ...
- 363
17
votes
2
answers
640
views
ReplaceRepeated seemingly omits some rules
Is there a simple way in Mathematica to prevent rule reordering? Let me give an example:
...
- 367
7
votes
5
answers
965
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 ...
- 525
8
votes
4
answers
713
views
4
votes
6
answers
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
10
votes
2
answers
360
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.
...
- 1,630
13
votes
1
answer
355
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 ...
- 4,291
3
votes
3
answers
2k
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 ...
- 1,040
1
vote
2
answers
401
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
5
votes
1
answer
1k
views
What do brackets around a levelspec option do?
The following code returns the first three integer elements of Sqrt[Range[100]]:
...
- 1,471
2
votes
5
answers
382
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
3
votes
1
answer
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 ...
- 20k
5
votes
1
answer
247
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
4
votes
1
answer
280
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.
...
- 1,239
6
votes
2
answers
244
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 ...
- 1,550
3
votes
2
answers
163
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
2
votes
1
answer
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
...
- 4,632
1
vote
1
answer
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
1
answer
61
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 ...
- 2,184
0
votes
0
answers
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:
...
- 73