New answers tagged map
11
votes
Accepted
Maps between finite sets
alist = {3, 4, 5};
blist = {"a", "b"};
mapfs = Tuples@Outer[Rule, blist, alist]
$$\begin{array}{l}
\{\text{a}\to 3,\text{b}\to 3\} \\
\{\text{...
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6
votes
Maps between finite sets
There's no built-in function but the following constructs the mappings:
...
- 213k
6
votes
Monitoring Apply / @@@ over large lists
Practically speaking, this is what I actually do:
First, if I need a variable to be dynamically updated, I use a global foo. Global side effects are generally a ...
- 213k
5
votes
Monitoring Apply / @@@ over large lists
You can do something like:
Module[{i},
result = Monitor[
Table[
Pause[0.1]; f @@ i,
{i, RandomReal[1, {20, 3}]}
],
i
]
]
The ...
- 17.9k
15
votes
Monitoring Apply / @@@ over large lists
You can always transform an expression of the form Apply[f,list,level] to the (almost) equivalent Map[Apply[f],list,level]. You ...
- 23.4k
8
votes
Accepted
Monitoring Apply / @@@ over large lists
Probably many ways to do this. For instance, imagine you got a list of large integers
list = Table[{RandomInteger[{10^20, 10^21}]}, 10]
for which you need to check ...
- 68.8k
6
votes
6
votes
How can I apply a function only to even-index elements of a list?
SubsetMap[dd, arr, 2 ;; -1 ;; 2]
(* {1, 3, 3, 5, 5} *)
where:
arr = {1, 2, 3, 4, 5};
dd[p_] := p + 1
Just for fun
...
- 10.4k
10
votes
How can I apply a function only to even-index elements of a list?
You can use the new ApplyTo:
A = {1, 2, 3, 4, 5};
Dd[P_] := P + 1
A[[2 ;; ;; 2]] //= Dd;
A
(* {1, 3, 3, 5, 5} *)
- 35.7k
11
votes
How can I apply a function only to even-index elements of a list?
I changed D to Dd:
MapAt[Dd, A, 2 ;; ;; 2]
- 3,807
8
votes
How can I apply a function only to even-index elements of a list?
alist = {1, 2, 3, 4, 5}
Using MapIndexed:
...
- 14.9k
4
votes
Smart way to remove rules from lists, leaving just values, specifically from FindMinimum output
Odds and ends
Single and two-variable examples:
...
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4
votes
Smart way to remove rules from lists, leaving just values, specifically from FindMinimum output
These methods work correctly with any number of variables of any dimensionality:
...
- 55.8k
7
votes
Accepted
Smart way to remove rules from lists, leaving just values, specifically from FindMinimum output
I want to add this reply in response to the comment written under the OP.
The function Values does not work, as all the elements of the list are not rules. (the ...
- 5,684
6
votes
Smart way to remove rules from lists, leaving just values, specifically from FindMinimum output
Let
ruleNixer = Rule[_, v_] :> v;
Example1 from the docs:
FindMinimum[x Cos[x], {x, 2}]
{-3.28837, {x -> 3.42562}}
<...
- 14.9k
5
votes
Smart way to remove rules from lists, leaving just values, specifically from FindMinimum output
If you're needing to handle output from FindMinimum specifically, then since you know that structure you know how to "re-structure" it:
...
- 3,807
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