Linked Questions

76 votes
3 answers

when is f@g not the same as f[g]?

I have always thought that f@g will give the same result as f[g] in all cases, and it is just a matter of style which one to use ...
Nasser's user avatar
  • 145k
37 votes
3 answers

How to Combine Pattern Constraints and Default Values for Function Arguments?

EDIT: As several respondents have noted in the answers and comments below, the original example had a default value that would never be used because of the way patterns and default values are ...
StackExchanger's user avatar
30 votes
3 answers

Parentheses in pure functions: # & vs. ( # &)

I've been using Mathematica for years, and over time I have developed the habit of using: Select[data, (# == 1 &)] instead of ...
Eric Brown's user avatar
  • 4,426
24 votes
3 answers

How can I get the unchanged Box form of an arbitrary expression?

One may observe that MakeBoxes does not give the actual Box form of various expressions: MakeBoxes[{1*^4, 000123, a*b c}] <...
Mr.Wizard's user avatar
  • 272k
18 votes
1 answer

Is there a guideline about when to end expressions with semicolons?

Whether for nested Ifs or within scoping constructs like Module and Block, I never know ...
Andrew Cheong's user avatar
17 votes
3 answers

What is the real default CellEvaluationFunction?

The default CellEvaluationFunction is Identity but one can quickly see that this is handled specially as an equivalent function, ...
Mr.Wizard's user avatar
  • 272k
15 votes
2 answers

Infix form of PutAppend ( >>> ) does not work with variable

I'm new to Mathematica, so I suspect this question involves either a misunderstanding involving variables or the usage of >>>. On a webMathematica page (...
Daniel's user avatar
  • 825
9 votes
3 answers

Metaquestion: how to find out why (e.g.) MatchQ[42, _?Function[x, True]] is False?

Suppose you run into a bewildering Mathematica result (which happens to me several times per Mathematica session, even after a 20-year acquaintance), such as, for example: ...
kjo's user avatar
  • 11.7k
9 votes
1 answer

Bug in grouping after editing code?

Bug introduced in 7.0 or earlier and persisting through 11.0 While looking at A question about conditional replacement I think I discovered a bug in the Front End that affects both 7.0.1 and 10.0.1 ...
Mr.Wizard's user avatar
  • 272k
6 votes
1 answer

create function that behaves like continuedFraction [duplicate]

I'm just starting to learn Mathematica and I got stuck at this question. This a noob question but please help. I need to define a function named continuedFraction that takes user input of type list ...
momokjaaaaa's user avatar
5 votes
2 answers

Associativity of `/@` [duplicate]

Why are the following not equivalent: Map[Line, Map[(Print[#]; #) &, {{{2, 1}, {1, 1}}, {{-2, 1}, {3, 1}}}]] which produces ...
d125q's user avatar
  • 437
5 votes
2 answers

Nested mapping of a function

If I use the construct f[#] & /@ f[#] & /@ f[#] & /@ {a, b, c} my function works, but if I use ...
martin's user avatar
  • 8,708
4 votes
1 answer

Association of pure functions [duplicate]

I've encountered confusing behavior of Association when I try to use it for storing pure functions. For example: as = <|"1" -> # + 1 &|> ...
iav's user avatar
  • 2,016
4 votes
1 answer

How to see abstract syntax tree of Wolfram Language expression

I mean, suppose I have this expression: 2 + 2 I want to get something like this: Plus[2, 2] as an output. I've tried FullForm, but this just evaluates 2+2 and returns 4. Is this even possible?
Ezo's user avatar
  • 43
3 votes
4 answers

Extracting RHS from Rule

In an example from another question, the rhs of a list of rules can be simply extracted: ...
ebergerson's user avatar

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