Questions tagged [placeholder]

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Recursive error encountered when updating rules of assignment [closed]

I'm working on a problem which requires associating a single (complex) number with a pair of binary vectors. I'm doing this by creating a set of assignments through a function I call ...
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How to implement integration by parts?

I have been trying to simplify integrand expressions using integration by parts, which schematically is given by $\theta(x)\nabla\phi(x)=-\phi(x)\nabla\theta(x)$. I think this can be done as a ...
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3 votes
1 answer
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How to make boxes independent from those cell-formatting options?

In a cell whose LanguageCategory option is "Input", boxes will be syntax-highlighted. Is there any way to diasble such ...
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1 vote
1 answer
91 views

Using # and ## in same statement to represent different levels

I am trying to write some codes to judge if each row of a matrix contains any negative numbers. For example mat = {{1, 2, 3}, {-1, 2, 3}, {0, 2, 3}}, and ...
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1 vote
1 answer
37 views

Notebook Apply with SelectionPlaceholder leaves entire pasted structure selected

Consider the following button: ...
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3 votes
1 answer
393 views

Replace rule using a wildcard

I have a complicated expression which I want to simplify following a rule. For example, if I want to make the following replacement: A[t] - B*A[t - d1] = Y[t] ...
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How to use multiple placeholders to define a function that operates on special functions.

I am trying to understand if and how I can use multiple placeholders in order to define a function that will perform more than one operations on special functions; more accurately, sums, products, etc ...
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5 votes
2 answers
127 views

MatchQ failing in some cases with Hold [duplicate]

Could someone clarify why the first of these MatchQ finds a match whereas the second does not? (I'm using version 10.0, in case that matters.) ...
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1 vote
2 answers
35 views

Place Holder or Suppressing Re-ordering

Using the for loop how can I print: file0.jpg file1.jpg file2.jpg file3.jpg file4.jpg file5.jpg file6.jpg file7.jpg file8.jpg file9.jpg The closest code I came ...
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3 votes
1 answer
93 views

How to use special characters in .m file?

I ran into a strange problem with a function that I want to include in a package file (.m): Cleanup[data_] := data /. (\[Placeholder] -> Missing[]) When I ...
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0 votes
1 answer
142 views

What is the simplest way to obtain function obect of a given function?

Suppose I have a function p of some arguments: p[x_,y_]:= (* something *) Now I with to pass this function as an object to ...
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