Hcfyk

Pre-Employment Background Check With Consent For Future Checks

What are rules for concealing thieves tools (or items in general)?

Norwegian Refugee travel document

Homology of the fiber

Does Shadow Sorcerer's Eyes of the Dark work on all magical darkness or just his/hers?

Acquisition - what happens to stock?

What is the tangent at a sharp point on a curve?

Can "few" be used as a subject? If so, what is the rule?

Hackerrank All Women's Codesprint 2019: Name the Product

Print a physical multiplication table

When should a starting writer get his own webpage?

Do native speakers use "ultima" and "proxima" frequently in spoken English?

pipe commands inside find -exec?

Align centered, ragged right and ragged left in align environment

10 year ban after applying for a UK student visa

How can a new country break out from a developed country without war?

How to remove space in section title at KOMA-Script

Why didn’t Eve recognize the little cockroach as a living organism?

Would this string work as string?

How to find the largest number(s) in a list of elements?

What is the difference between something being completely legal and being completely decriminalized?

Nested Dynamic SOQL Query

UK Tourist Visa- Enquiry

In the backstop position will the UK be able to negotiate FTAs?

How to write a list literal with conditional items? [duplicate]

How to evaluate the variables before adding them to a list?Creating an association list with element evaluationHow to write assertionshow to access/print a list of a list?How to remove / delete nth element of a listWrapper objects / types for Emacs Lisp primitives?How to create and traverse a multidimensional listHow to wrap a single string literal across multiple lines?How do I rotate list elements?Adding many items to a listHow to delete all list elements matching a regexp?

2

This question already has an answer here:

• 
  How to evaluate the variables before adding them to a list?
  
  2 answers
  
  

Given a list literal '(1 2 3)

is it possible to conditionally include parts of the list?

eg:

'(1 2 3
 (when thing-is-true '(10 11 12)))
 4 5 6)

Which would result in

'(1 2 3 4 5 6) or '(1 2 3 10 11 12 4 5 6) dependent on thing-is-true.

---

Python for example supports:

[1, 2, 3, *([10, 11, 12] if thing_is_true else []), 4, 5, 6]

---

What is the most straightforward way to achieve this using a single expression, without defining a list variable and manipulating it?

elisp list

share|improve this question

edited yesterday

ideasman42

asked yesterday

ideasman42ideasman42

1,555625

marked as duplicate by npostavs, DoMiNeLa10♦ yesterday

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Don't think this is a duplicate because I'm not asking about adding items to a list. Rather, how to declare a list. Also notice the answer to this question is quite different.
  
  – ideasman42
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Hmm, I guess there is minor difference in that the dup's answer doesn't mention ,@, only ,; but to my mind the answer in both cases is essentially: "you're looking for backquote".
  
  – npostavs
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I was aware of the feature (that it could be useful in this case), I just didn't know how to use it because I'm not that experienced in elisp.
  
  – ideasman42
  yesterday
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I'm not aware of what you're aware of, I just talk about what's written in the question and vote accordingly.
  
  – npostavs
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Seems like a dup to me, regardless of a minor difference in what you're trying to do. The question is really about a misunderstanding, and the referenced duplicate Q&A covers that. (And the tags should include quote and not include elisp, IMO.)
  
  – Drew
  yesterday
  

  
  
  
  

 | 
show 1 more comment

2

This question already has an answer here:

• 
  How to evaluate the variables before adding them to a list?
  
  2 answers
  
  

Given a list literal '(1 2 3)

is it possible to conditionally include parts of the list?

eg:

'(1 2 3
 (when thing-is-true '(10 11 12)))
 4 5 6)

Which would result in

'(1 2 3 4 5 6) or '(1 2 3 10 11 12 4 5 6) dependent on thing-is-true.

---

Python for example supports:

[1, 2, 3, *([10, 11, 12] if thing_is_true else []), 4, 5, 6]

---

What is the most straightforward way to achieve this using a single expression, without defining a list variable and manipulating it?

elisp list

share|improve this question

edited yesterday

ideasman42

asked yesterday

ideasman42ideasman42

1,555625

marked as duplicate by npostavs, DoMiNeLa10♦ yesterday

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Don't think this is a duplicate because I'm not asking about adding items to a list. Rather, how to declare a list. Also notice the answer to this question is quite different.
  
  – ideasman42
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Hmm, I guess there is minor difference in that the dup's answer doesn't mention ,@, only ,; but to my mind the answer in both cases is essentially: "you're looking for backquote".
  
  – npostavs
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  I was aware of the feature (that it could be useful in this case), I just didn't know how to use it because I'm not that experienced in elisp.
  
  – ideasman42
  yesterday
  

  
  
  
  


• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I'm not aware of what you're aware of, I just talk about what's written in the question and vote accordingly.
  
  – npostavs
  yesterday
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Seems like a dup to me, regardless of a minor difference in what you're trying to do. The question is really about a misunderstanding, and the referenced duplicate Q&A covers that. (And the tags should include quote and not include elisp, IMO.)
  
  – Drew
  yesterday
  

  
  
  
  

 | 
show 1 more comment

This question already has an answer here:

• 
  How to evaluate the variables before adding them to a list?
  
  2 answers
  
  

Given a list literal '(1 2 3)

is it possible to conditionally include parts of the list?

eg:

'(1 2 3
 (when thing-is-true '(10 11 12)))
 4 5 6)

Which would result in

'(1 2 3 4 5 6) or '(1 2 3 10 11 12 4 5 6) dependent on thing-is-true.

---

Python for example supports:

[1, 2, 3, *([10, 11, 12] if thing_is_true else []), 4, 5, 6]

---

What is the most straightforward way to achieve this using a single expression, without defining a list variable and manipulating it?

elisp list

share|improve this question

edited yesterday

ideasman42

asked yesterday

ideasman42ideasman42

1,555625

'(1 2 3
 (when thing-is-true '(10 11 12)))
 4 5 6)

[1, 2, 3, *([10, 11, 12] if thing_is_true else []), 4, 5, 6]

share|improve this question

edited yesterday

ideasman42

asked yesterday

ideasman42ideasman42

1,555625

share|improve this question

edited yesterday

ideasman42

asked yesterday

ideasman42ideasman42

1,555625

asked yesterday

ideasman42ideasman42

1,555625

asked yesterday

ideasman42ideasman42

1,555625

1 Answer
1

active

oldest

votes

2

You can use the macro (elisp) Backquote, e.g.,

`(1 2 3 ,@(when nil '(10 11 12)) 4 5 6)
;; => (1 2 3 4 5 6)

`(1 2 3 ,@(when t '(10 11 12)) 4 5 6)
;; => (1 2 3 10 11 12 4 5 6)

if you expand the above macros, they are simply using append

(append '(1 2 3) (when nil '(10 11 12)) '(4 5 6))
;; => (1 2 3 4 5 6)

(append '(1 2 3) (when t '(10 11 12)) '(4 5 6))
;; => (1 2 3 10 11 12 4 5 6)

share|improve this answer

answered yesterday

xuchunyangxuchunyang

8,8941926

add a comment | 

2

You can use the macro (elisp) Backquote, e.g.,

`(1 2 3 ,@(when nil '(10 11 12)) 4 5 6)
;; => (1 2 3 4 5 6)

`(1 2 3 ,@(when t '(10 11 12)) 4 5 6)
;; => (1 2 3 10 11 12 4 5 6)

if you expand the above macros, they are simply using append

(append '(1 2 3) (when nil '(10 11 12)) '(4 5 6))
;; => (1 2 3 4 5 6)

(append '(1 2 3) (when t '(10 11 12)) '(4 5 6))
;; => (1 2 3 10 11 12 4 5 6)

share|improve this answer

answered yesterday

xuchunyangxuchunyang

8,8941926

add a comment | 

2

You can use the macro (elisp) Backquote, e.g.,

`(1 2 3 ,@(when nil '(10 11 12)) 4 5 6)
;; => (1 2 3 4 5 6)

`(1 2 3 ,@(when t '(10 11 12)) 4 5 6)
;; => (1 2 3 10 11 12 4 5 6)

if you expand the above macros, they are simply using append

(append '(1 2 3) (when nil '(10 11 12)) '(4 5 6))
;; => (1 2 3 4 5 6)

(append '(1 2 3) (when t '(10 11 12)) '(4 5 6))
;; => (1 2 3 10 11 12 4 5 6)

share|improve this answer

answered yesterday

xuchunyangxuchunyang

8,8941926

add a comment | 

You can use the macro (elisp) Backquote, e.g.,

`(1 2 3 ,@(when nil '(10 11 12)) 4 5 6)
;; => (1 2 3 4 5 6)

`(1 2 3 ,@(when t '(10 11 12)) 4 5 6)
;; => (1 2 3 10 11 12 4 5 6)

if you expand the above macros, they are simply using append

(append '(1 2 3) (when nil '(10 11 12)) '(4 5 6))
;; => (1 2 3 4 5 6)

(append '(1 2 3) (when t '(10 11 12)) '(4 5 6))
;; => (1 2 3 10 11 12 4 5 6)

share|improve this answer

answered yesterday

xuchunyangxuchunyang

8,8941926

`(1 2 3 ,@(when nil '(10 11 12)) 4 5 6)
;; => (1 2 3 4 5 6)

`(1 2 3 ,@(when t '(10 11 12)) 4 5 6)
;; => (1 2 3 10 11 12 4 5 6)

(append '(1 2 3) (when nil '(10 11 12)) '(4 5 6))
;; => (1 2 3 4 5 6)

(append '(1 2 3) (when t '(10 11 12)) '(4 5 6))
;; => (1 2 3 10 11 12 4 5 6)

share|improve this answer

answered yesterday

xuchunyangxuchunyang

8,8941926

answered yesterday

xuchunyangxuchunyang

8,8941926

answered yesterday

xuchunyangxuchunyang

8,8941926