Mfcttrf

Wrapper in return method for test class

How do I determine whether a permit is required for a new gas line?

Was the Ford Model T black because of the speed black paint dries?

Correct use of ergeben?

If a specific mass of air is polluted, will the pollution stick with it?

Was adding milk to tea started to reduce employee tea break time?

Where is the USB2 OTG port on the RPi 4 Model B located?

Do you make saves against the Web spell as you move through it?

<schwitz>, <zwinker> etc. Does German always use 2nd Person Singular Imperative verbs for emoticons? If so, why?

Are there any double stars that I can actually see orbit each other?

What can the U.S. government do to prevent powerful people to get extremely favorable plea bargain deals like Jeff Epstein?

How were hypergolic propellants delivered to the Shuttle launch pad?

Cubic programming and beyond?

What's the fastest way to get Hard To Borrow (HTB) stocks?

Why did my rum cake turn black?

Optimising Table wrapping over a Select

Who Can Help Retag This?

I have a ruthless DM and I'm considering leaving the party. What are my options to minimize the negative impact to the rest of the group?

Filtering fine silt/mud from water (not necessarily bacteria etc.)

Why isn't there research to build a standard lunar, or Martian mobility platform?

What is this welding tool I found in my attic?

Professor falsely accusing me of cheating in a class he does not teach, two months after end of the class. What precautions should I take?

Does Google Maps take into account hills/inclines for route times?

Credit union holding car note, refuses to provide details of how payments have been applied

Returning the argument of a function if the argument is not of the right type

Function argument to default under certain conditionDefine a function on a parameter argument set to zeroHow to make a function with its own options as well as passing options to other functionsCan I make a function which depends on several arguments which are not independent?Supply a function as an argument to another, and find its minimumTake the derivative of a function of time by another function of timeRemembering Previously Evaluated Function Values with Optional ArgumentImposing conditions on argument for a function definitionHow to make functional rules not depend on an argument?Saving remembered function when closing down notebook

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;

2

$begingroup$

Best to give an example. Let us consider the function AdjacencyMatrix. When we pass, say a matrix to it, we get:

test = 1,1,1,1,2,2,3,3,3;
AdjacencyMatrix[%]

AdjacencyMatrix::graph: A graph object is expected at position 1 in AdjacencyMatrix[1,1,1,1,2,2,3,3,3].

AdjacencyMatrix[1, 1, 1, 1, 2, 2, 3, 3, 3]

Is there a way of modifying AdjacencyMatrix so that if the argument isn't a graph object it would simply return the argument itself?

functions attributes

share|improve this question

asked 9 hours ago

amator2357amator2357

8121010 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  You want AdjacencyMatrix to return the argument itself only when it is a matrix, or whenever it is not a graph?
  $endgroup$
  – AccidentalFourierTransform
  8 hours ago
  

  
  
  
  

add a comment | 

2

$begingroup$

Best to give an example. Let us consider the function AdjacencyMatrix. When we pass, say a matrix to it, we get:

test = 1,1,1,1,2,2,3,3,3;
AdjacencyMatrix[%]

AdjacencyMatrix::graph: A graph object is expected at position 1 in AdjacencyMatrix[1,1,1,1,2,2,3,3,3].

AdjacencyMatrix[1, 1, 1, 1, 2, 2, 3, 3, 3]

Is there a way of modifying AdjacencyMatrix so that if the argument isn't a graph object it would simply return the argument itself?

functions attributes

share|improve this question

asked 9 hours ago

amator2357amator2357

8121010 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  You want AdjacencyMatrix to return the argument itself only when it is a matrix, or whenever it is not a graph?
  $endgroup$
  – AccidentalFourierTransform
  8 hours ago
  

  
  
  
  

add a comment | 

$begingroup$

Best to give an example. Let us consider the function AdjacencyMatrix. When we pass, say a matrix to it, we get:

test = 1,1,1,1,2,2,3,3,3;
AdjacencyMatrix[%]

AdjacencyMatrix::graph: A graph object is expected at position 1 in AdjacencyMatrix[1,1,1,1,2,2,3,3,3].

AdjacencyMatrix[1, 1, 1, 1, 2, 2, 3, 3, 3]

Is there a way of modifying AdjacencyMatrix so that if the argument isn't a graph object it would simply return the argument itself?

functions attributes

share|improve this question

asked 9 hours ago

amator2357amator2357

8121010 bronze badges

$endgroup$

test = 1,1,1,1,2,2,3,3,3;
AdjacencyMatrix[%]

share|improve this question

asked 9 hours ago

amator2357amator2357

8121010 bronze badges

share|improve this question

asked 9 hours ago

amator2357amator2357

8121010 bronze badges

asked 9 hours ago

amator2357amator2357

8121010 bronze badges

asked 9 hours ago

amator2357amator2357

8121010 bronze badges

2 Answers
2

active

oldest

votes

4

$begingroup$

You can use Check in a user defined function:

adjacencyMatrix[g_] := Check[AdjacencyMatrix[g], g]

Then:

adjacencyMatrix[Graph[1->2,2->3,3->4]] //Normal
adjacencyMatrix[1->2, 2->3, 3->4] //Normal
adjacencyMatrix[1,2,3,4]

0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0

0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0

AdjacencyMatrix::graph: A graph object is expected at position 1 in AdjacencyMatrix[1,2,3,4].

1, 2, 3, 4

share|improve this answer

answered 8 hours ago

Carl WollCarl Woll

86.8k33 gold badges114114 silver badges221221 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  This is much better than my approach. Note: OP may want to suppress the error message here: Quiet[Check[...], AdjacencyMatrix::graph].
  $endgroup$
  – AccidentalFourierTransform
  33 mins ago
  

  
  
  
  

add a comment | 

4

$begingroup$

Bad answer:

Unprotect[AdjacencyMatrix];
AdjacencyMatrix[mat_List] := mat
Protect[AdjacencyMatrix];

Good answer:

adjacencyMatrix[graph_Graph] := AdjacencyMatrix[graph]
adjacencyMatrix[mat_List] := mat

share|improve this answer

answered 9 hours ago

AccidentalFourierTransformAccidentalFourierTransform

6,29711 gold badge1212 silver badges4545 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  For the good answer, maybe remove the pattern head List on the second line, as this is the behavior requested for anything that's not a Graph.
  $endgroup$
  – Roman
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @Roman good point. Let me ask OP to be sure. (If they only want the identity for matrices, then it is safer to leave List in).
  $endgroup$
  – AccidentalFourierTransform
  8 hours ago
  

  
  
  
  

add a comment | 

Your Answer

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "387"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathematica.stackexchange.com%2fquestions%2f201998%2freturning-the-argument-of-a-function-if-the-argument-is-not-of-the-right-type%23new-answer', 'question_page');

);

Post as a guest

Name

Email

Required, but never shown

4

$begingroup$

You can use Check in a user defined function:

adjacencyMatrix[g_] := Check[AdjacencyMatrix[g], g]

Then:

adjacencyMatrix[Graph[1->2,2->3,3->4]] //Normal
adjacencyMatrix[1->2, 2->3, 3->4] //Normal
adjacencyMatrix[1,2,3,4]

0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0

0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0

AdjacencyMatrix::graph: A graph object is expected at position 1 in AdjacencyMatrix[1,2,3,4].

1, 2, 3, 4

share|improve this answer

answered 8 hours ago

Carl WollCarl Woll

86.8k33 gold badges114114 silver badges221221 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  This is much better than my approach. Note: OP may want to suppress the error message here: Quiet[Check[...], AdjacencyMatrix::graph].
  $endgroup$
  – AccidentalFourierTransform
  33 mins ago
  

  
  
  
  

add a comment | 

4

$begingroup$

You can use Check in a user defined function:

adjacencyMatrix[g_] := Check[AdjacencyMatrix[g], g]

Then:

adjacencyMatrix[Graph[1->2,2->3,3->4]] //Normal
adjacencyMatrix[1->2, 2->3, 3->4] //Normal
adjacencyMatrix[1,2,3,4]

0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0

0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0

AdjacencyMatrix::graph: A graph object is expected at position 1 in AdjacencyMatrix[1,2,3,4].

1, 2, 3, 4

share|improve this answer

answered 8 hours ago

Carl WollCarl Woll

86.8k33 gold badges114114 silver badges221221 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  This is much better than my approach. Note: OP may want to suppress the error message here: Quiet[Check[...], AdjacencyMatrix::graph].
  $endgroup$
  – AccidentalFourierTransform
  33 mins ago
  

  
  
  
  

add a comment | 

$begingroup$

You can use Check in a user defined function:

adjacencyMatrix[g_] := Check[AdjacencyMatrix[g], g]

Then:

adjacencyMatrix[Graph[1->2,2->3,3->4]] //Normal
adjacencyMatrix[1->2, 2->3, 3->4] //Normal
adjacencyMatrix[1,2,3,4]

0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0

0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0

AdjacencyMatrix::graph: A graph object is expected at position 1 in AdjacencyMatrix[1,2,3,4].

1, 2, 3, 4

share|improve this answer

answered 8 hours ago

Carl WollCarl Woll

86.8k33 gold badges114114 silver badges221221 bronze badges

$endgroup$

adjacencyMatrix[g_] := Check[AdjacencyMatrix[g], g]

adjacencyMatrix[Graph[1->2,2->3,3->4]] //Normal
adjacencyMatrix[1->2, 2->3, 3->4] //Normal
adjacencyMatrix[1,2,3,4]

share|improve this answer

answered 8 hours ago

Carl WollCarl Woll

86.8k33 gold badges114114 silver badges221221 bronze badges

answered 8 hours ago

Carl WollCarl Woll

86.8k33 gold badges114114 silver badges221221 bronze badges

answered 8 hours ago

Carl WollCarl Woll

86.8k33 gold badges114114 silver badges221221 bronze badges

4

$begingroup$

Bad answer:

Unprotect[AdjacencyMatrix];
AdjacencyMatrix[mat_List] := mat
Protect[AdjacencyMatrix];

Good answer:

adjacencyMatrix[graph_Graph] := AdjacencyMatrix[graph]
adjacencyMatrix[mat_List] := mat

share|improve this answer

answered 9 hours ago

AccidentalFourierTransformAccidentalFourierTransform

6,29711 gold badge1212 silver badges4545 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  For the good answer, maybe remove the pattern head List on the second line, as this is the behavior requested for anything that's not a Graph.
  $endgroup$
  – Roman
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @Roman good point. Let me ask OP to be sure. (If they only want the identity for matrices, then it is safer to leave List in).
  $endgroup$
  – AccidentalFourierTransform
  8 hours ago
  

  
  
  
  

add a comment | 

4

$begingroup$

Bad answer:

Unprotect[AdjacencyMatrix];
AdjacencyMatrix[mat_List] := mat
Protect[AdjacencyMatrix];

Good answer:

adjacencyMatrix[graph_Graph] := AdjacencyMatrix[graph]
adjacencyMatrix[mat_List] := mat

share|improve this answer

answered 9 hours ago

AccidentalFourierTransformAccidentalFourierTransform

6,29711 gold badge1212 silver badges4545 bronze badges

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  For the good answer, maybe remove the pattern head List on the second line, as this is the behavior requested for anything that's not a Graph.
  $endgroup$
  – Roman
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @Roman good point. Let me ask OP to be sure. (If they only want the identity for matrices, then it is safer to leave List in).
  $endgroup$
  – AccidentalFourierTransform
  8 hours ago
  

  
  
  
  

add a comment | 

$begingroup$

Bad answer:

Unprotect[AdjacencyMatrix];
AdjacencyMatrix[mat_List] := mat
Protect[AdjacencyMatrix];

Good answer:

adjacencyMatrix[graph_Graph] := AdjacencyMatrix[graph]
adjacencyMatrix[mat_List] := mat

share|improve this answer

answered 9 hours ago

AccidentalFourierTransformAccidentalFourierTransform

6,29711 gold badge1212 silver badges4545 bronze badges

$endgroup$

Unprotect[AdjacencyMatrix];
AdjacencyMatrix[mat_List] := mat
Protect[AdjacencyMatrix];

adjacencyMatrix[graph_Graph] := AdjacencyMatrix[graph]
adjacencyMatrix[mat_List] := mat

share|improve this answer

answered 9 hours ago

AccidentalFourierTransformAccidentalFourierTransform

6,29711 gold badge1212 silver badges4545 bronze badges

answered 9 hours ago

AccidentalFourierTransformAccidentalFourierTransform

6,29711 gold badge1212 silver badges4545 bronze badges

answered 9 hours ago

AccidentalFourierTransformAccidentalFourierTransform

6,29711 gold badge1212 silver badges4545 bronze badges