Arsthbt

Can I find out the caloric content of bread by dehydrating it?

Shall I use personal or official e-mail account when registering to external websites for work purpose?

Travelling to Edinburgh from India

How to deal with fear of taking dependencies

Symmetry in quantum mechanics

Landlord wants to switch my lease to a "Land contract" to "get back at the city"

Can a planet have a different gravitational pull depending on its location in orbit around its sun?

Eliminate empty elements from a list with a specific pattern

Why doesn't a const reference extend the life of a temporary object passed via a function?

When blogging recipes, how can I support both readers who want the narrative/journey and ones who want the printer-friendly recipe?

Is Fable (1996) connected in any way to the Fable franchise from Lionhead Studios?

Is this homebrew feat, Beast of Burden, balanced?

Imbalanced dataset binary classification

How to answer pointed "are you quitting" questioning when I don't want them to suspect

Could a US political party gain complete control over the government by removing checks & balances?

Does a dangling wire really electrocute me if I'm standing in water?

Copycat chess is back

Crop image to path created in TikZ?

What do the Banks children have against barley water?

Is it legal to have the "// (c) 2019 John Smith" header in all files when there are hundreds of contributors?

Doomsday-clock for my fantasy planet

How to create a consistant feel for character names in a fantasy setting?

Is every set a filtered colimit of finite sets?

Information to fellow intern about hiring?

Eliminate empty elements from a list with a specific pattern

List operation on specific elementsSelect elements from list with given headSelecting elements from a list with nullsReplace empty list elements with patternReplacing Non-Constant Elements from List with Patternselecting elements from a list with two numbersRemoving elements of a specific length from a listEliminate types of elements from the listListPlot3D with empty matrix elementsDelete a large pattern from one list

3

1

$begingroup$

I am really new in this patterns part of Mathematica. Basically what I need to do is eliminate null elements from a list but that has a specific name before the empty element. For example, my list is:

list="a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2"

and I need to obtain

list="a12-b11-1", "d33-c22-2"

The list was created using

list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> 
 ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], 
 i, 1, 4, j, 1, 4], 1]

and for some values it writtes because there is not a value equal to $0.5$. Until now I have been able to do it term by term as

list//."a11-b11-"-> Sequence[]

but the real list contains a lot of elements and could be almost impossible to do it that way to solve the problem. I think my main problem is that I am not sure how to specify the pattern search (something like " *-name " in gnu/linux). Is there a wise way to do this?. Thanks in advance.

list-manipulation filtering

share|improve this question

edited 1 hour ago

Roman

4,64511128

asked 6 hours ago

morsmors

496

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Have a look at DeleteCases and StringMatchQ or StringContainsQ.
  $endgroup$
  – b.gatessucks
  6 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I think it would be more efficient to first filter out the unwanted cases in the int function, and then construct strings only from the remaining ones.
  $endgroup$
  – Roman
  5 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @b.gatessucks Thank you, I will look those option in Mathematica.
  $endgroup$
  – mors
  5 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @Roman You are right, but I am new ih this cases stuf in Mathematica and I did no know how to do it when I created the list.
  $endgroup$
  – mors
  5 hours ago
  

  
  
  
  

add a comment | 

3

1

$begingroup$

I am really new in this patterns part of Mathematica. Basically what I need to do is eliminate null elements from a list but that has a specific name before the empty element. For example, my list is:

list="a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2"

and I need to obtain

list="a12-b11-1", "d33-c22-2"

The list was created using

list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> 
 ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], 
 i, 1, 4, j, 1, 4], 1]

and for some values it writtes because there is not a value equal to $0.5$. Until now I have been able to do it term by term as

list//."a11-b11-"-> Sequence[]

but the real list contains a lot of elements and could be almost impossible to do it that way to solve the problem. I think my main problem is that I am not sure how to specify the pattern search (something like " *-name " in gnu/linux). Is there a wise way to do this?. Thanks in advance.

list-manipulation filtering

share|improve this question

edited 1 hour ago

Roman

4,64511128

asked 6 hours ago

morsmors

496

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Have a look at DeleteCases and StringMatchQ or StringContainsQ.
  $endgroup$
  – b.gatessucks
  6 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  I think it would be more efficient to first filter out the unwanted cases in the int function, and then construct strings only from the remaining ones.
  $endgroup$
  – Roman
  5 hours ago
  
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @b.gatessucks Thank you, I will look those option in Mathematica.
  $endgroup$
  – mors
  5 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  @Roman You are right, but I am new ih this cases stuf in Mathematica and I did no know how to do it when I created the list.
  $endgroup$
  – mors
  5 hours ago
  

  
  
  
  

add a comment | 

$begingroup$

I am really new in this patterns part of Mathematica. Basically what I need to do is eliminate null elements from a list but that has a specific name before the empty element. For example, my list is:

list="a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2"

and I need to obtain

list="a12-b11-1", "d33-c22-2"

The list was created using

list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> 
 ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], 
 i, 1, 4, j, 1, 4], 1]

and for some values it writtes because there is not a value equal to $0.5$. Until now I have been able to do it term by term as

list//."a11-b11-"-> Sequence[]

but the real list contains a lot of elements and could be almost impossible to do it that way to solve the problem. I think my main problem is that I am not sure how to specify the pattern search (something like " *-name " in gnu/linux). Is there a wise way to do this?. Thanks in advance.

list-manipulation filtering

share|improve this question

edited 1 hour ago

Roman

4,64511128

asked 6 hours ago

morsmors

496

$endgroup$

list="a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2"

list="a12-b11-1", "d33-c22-2"

list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> 
 ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], 
 i, 1, 4, j, 1, 4], 1]

list//."a11-b11-"-> Sequence[]

share|improve this question

edited 1 hour ago

Roman

4,64511128

asked 6 hours ago

morsmors

496

share|improve this question

edited 1 hour ago

Roman

4,64511128

asked 6 hours ago

morsmors

496

edited 1 hour ago

Roman

4,64511128

edited 1 hour ago

Roman

4,64511128

asked 6 hours ago

morsmors

496

asked 6 hours ago

morsmors

496

2 Answers
2

active

oldest

votes

7

$begingroup$

If the list elements are strings, as it appears after your comment, you can use Select with a string pattern:

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringMatchQ[__ ~~ ""]]

"a12-b11-1", "d33-c22-2"

You could also Select before making the strings:

L = DeleteCases[
 Flatten[
 Table[
 namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1],
 i, 4, j, 4],
 1],
 _, _, ];

and then make these into strings:

StringRiffle[ToString /@ #, "-"] & /@ L

I can't check this because you didn't supply functioning code.

share|improve this answer

edited 2 hours ago

answered 6 hours ago

RomanRoman

4,64511128

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], i, 1, 4, j, 1, 4], 1] '
  $endgroup$
  – mors
  6 hours ago
  
  

  
  
  
  

add a comment | 

0

$begingroup$

In 10.1, two functions were added to handle a pair of very common cases: StringStartsQ and StringEndsQ which return True if the string matches a pattern at the beginning or end, respectively. So, while Roman's answer gives you the full general form, most of the pattern can be eliminated by using

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringEndsQ[""]]

instead.

share|improve this answer

answered 11 mins ago

rcollyerrcollyer

28.6k674166

$endgroup$

add a comment | 

Your Answer

StackExchange.ifUsing("editor", function ()
return StackExchange.using("mathjaxEditing", function ()
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
);
);
, "mathjax-editing");

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%2f194815%2feliminate-empty-elements-from-a-list-with-a-specific-pattern%23new-answer', 'question_page');

);

Post as a guest

Name

Email

Required, but never shown

7

$begingroup$

If the list elements are strings, as it appears after your comment, you can use Select with a string pattern:

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringMatchQ[__ ~~ ""]]

"a12-b11-1", "d33-c22-2"

You could also Select before making the strings:

L = DeleteCases[
 Flatten[
 Table[
 namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1],
 i, 4, j, 4],
 1],
 _, _, ];

and then make these into strings:

StringRiffle[ToString /@ #, "-"] & /@ L

I can't check this because you didn't supply functioning code.

share|improve this answer

edited 2 hours ago

answered 6 hours ago

RomanRoman

4,64511128

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], i, 1, 4, j, 1, 4], 1] '
  $endgroup$
  – mors
  6 hours ago
  
  

  
  
  
  

add a comment | 

7

$begingroup$

If the list elements are strings, as it appears after your comment, you can use Select with a string pattern:

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringMatchQ[__ ~~ ""]]

"a12-b11-1", "d33-c22-2"

You could also Select before making the strings:

L = DeleteCases[
 Flatten[
 Table[
 namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1],
 i, 4, j, 4],
 1],
 _, _, ];

and then make these into strings:

StringRiffle[ToString /@ #, "-"] & /@ L

I can't check this because you didn't supply functioning code.

share|improve this answer

edited 2 hours ago

answered 6 hours ago

RomanRoman

4,64511128

$endgroup$

• 
  
  
  

  
  

  
  
  
  
  
  

  
  $begingroup$
  Thank you, I forgot to specify the way the list is created. I create the list as 'list = Flatten[Table[ ToString[namea[[i]] <> "-" <> nameb[[j]] <> "-" <> ToString[ Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1] ]], i, 1, 4, j, 1, 4], 1] '
  $endgroup$
  – mors
  6 hours ago
  
  

  
  
  
  

add a comment | 

$begingroup$

If the list elements are strings, as it appears after your comment, you can use Select with a string pattern:

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringMatchQ[__ ~~ ""]]

"a12-b11-1", "d33-c22-2"

You could also Select before making the strings:

L = DeleteCases[
 Flatten[
 Table[
 namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1],
 i, 4, j, 4],
 1],
 _, _, ];

and then make these into strings:

StringRiffle[ToString /@ #, "-"] & /@ L

I can't check this because you didn't supply functioning code.

share|improve this answer

edited 2 hours ago

answered 6 hours ago

RomanRoman

4,64511128

$endgroup$

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringMatchQ[__ ~~ ""]]

L = DeleteCases[
 Flatten[
 Table[
 namea[[i]], nameb[[j]], Select[int[i, j, 0.5], Abs[#] == 0.5 &, 1],
 i, 4, j, 4],
 1],
 _, _, ];

StringRiffle[ToString /@ #, "-"] & /@ L

share|improve this answer

edited 2 hours ago

answered 6 hours ago

RomanRoman

4,64511128

answered 6 hours ago

RomanRoman

4,64511128

answered 6 hours ago

RomanRoman

4,64511128

0

$begingroup$

In 10.1, two functions were added to handle a pair of very common cases: StringStartsQ and StringEndsQ which return True if the string matches a pattern at the beginning or end, respectively. So, while Roman's answer gives you the full general form, most of the pattern can be eliminated by using

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringEndsQ[""]]

instead.

share|improve this answer

answered 11 mins ago

rcollyerrcollyer

28.6k674166

$endgroup$

add a comment | 

0

$begingroup$

In 10.1, two functions were added to handle a pair of very common cases: StringStartsQ and StringEndsQ which return True if the string matches a pattern at the beginning or end, respectively. So, while Roman's answer gives you the full general form, most of the pattern can be eliminated by using

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringEndsQ[""]]

instead.

share|improve this answer

answered 11 mins ago

rcollyerrcollyer

28.6k674166

$endgroup$

add a comment | 

$begingroup$

In 10.1, two functions were added to handle a pair of very common cases: StringStartsQ and StringEndsQ which return True if the string matches a pattern at the beginning or end, respectively. So, while Roman's answer gives you the full general form, most of the pattern can be eliminated by using

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringEndsQ[""]]

instead.

share|improve this answer

answered 11 mins ago

rcollyerrcollyer

28.6k674166

$endgroup$

list = "a11-b11-", "a12-b11-1", "c11-d22-", "d33-c22-2";
Select[list, Not@*StringEndsQ[""]]

share|improve this answer

answered 11 mins ago

rcollyerrcollyer

28.6k674166

answered 11 mins ago

rcollyerrcollyer

28.6k674166

answered 11 mins ago

rcollyerrcollyer

28.6k674166