Set all vector elements to NA in a list of vectors

How can I set all vector elements to NA in a list of vectors?

Essentially, I'd like to keep an existing list's structure and names but empty all values, to fill them in later. I provide a minimal example with a couple solutions below. I prefer base and tidyverse (esp. purrr) solutions, but can get on board with any approach which is better than what I have below.

my_list <- list(A = c('a' = 1, 'b' = 2, 'c' = 3), B = c('x' = 10, 'y' = 20))

ret_list <- my_list



# Approach 1

for (element_name in names(my_list)) {

  ret_list[[element_name]] <- NA

}



ret_list

# $A

# a  b  c 

# NA NA NA 

# 

# $B

# x  y 

# NA NA 



# Approach 2    

lapply(my_list, function(x) {x <- NA; return(x)})

# $A

# a  b  c 

# NA NA NA 

# 

# $B

# x  y 

# NA NA

edited Jan 1 at 0:02

asked Dec 31 '18 at 22:56

lowndrul

1,16521835

1

both approaches seem fine to me (especially if you define the function in Approach 2 beforehand rather than anonymously inline). Why try to be cleverer than that? What specific shortcomings would you like to remedy?
– Ben Bolker
Dec 31 '18 at 23:27

1

Just taking an opportunity to understand R a little better. It seemed to me that this was such a common operation that there had to be a standard, best-practices approach.
– lowndrul
Dec 31 '18 at 23:40

add a comment |

How can I set all vector elements to NA in a list of vectors?

my_list <- list(A = c('a' = 1, 'b' = 2, 'c' = 3), B = c('x' = 10, 'y' = 20))

ret_list <- my_list



# Approach 1

for (element_name in names(my_list)) {

  ret_list[[element_name]] <- NA

}



ret_list

# $A

# a  b  c 

# NA NA NA 

# 

# $B

# x  y 

# NA NA 



# Approach 2    

lapply(my_list, function(x) {x <- NA; return(x)})

# $A

# a  b  c 

# NA NA NA 

# 

# $B

# x  y 

# NA NA

edited Jan 1 at 0:02

asked Dec 31 '18 at 22:56

lowndrul

1,16521835

1

both approaches seem fine to me (especially if you define the function in Approach 2 beforehand rather than anonymously inline). Why try to be cleverer than that? What specific shortcomings would you like to remedy?
– Ben Bolker
Dec 31 '18 at 23:27

1

Just taking an opportunity to understand R a little better. It seemed to me that this was such a common operation that there had to be a standard, best-practices approach.
– lowndrul
Dec 31 '18 at 23:40

add a comment |

How can I set all vector elements to NA in a list of vectors?

my_list <- list(A = c('a' = 1, 'b' = 2, 'c' = 3), B = c('x' = 10, 'y' = 20))

ret_list <- my_list



# Approach 1

for (element_name in names(my_list)) {

  ret_list[[element_name]] <- NA

}



ret_list

# $A

# a  b  c 

# NA NA NA 

# 

# $B

# x  y 

# NA NA 



# Approach 2    

lapply(my_list, function(x) {x <- NA; return(x)})

# $A

# a  b  c 

# NA NA NA 

# 

# $B

# x  y 

# NA NA

edited Jan 1 at 0:02

asked Dec 31 '18 at 22:56

lowndrul

1,16521835

How can I set all vector elements to NA in a list of vectors?

my_list <- list(A = c('a' = 1, 'b' = 2, 'c' = 3), B = c('x' = 10, 'y' = 20))

ret_list <- my_list



# Approach 1

for (element_name in names(my_list)) {

  ret_list[[element_name]] <- NA

}



ret_list

# $A

# a  b  c 

# NA NA NA 

# 

# $B

# x  y 

# NA NA 



# Approach 2    

lapply(my_list, function(x) {x <- NA; return(x)})

# $A

# a  b  c 

# NA NA NA 

# 

# $B

# x  y 

# NA NA

edited Jan 1 at 0:02

asked Dec 31 '18 at 22:56

lowndrul

1,16521835

edited Jan 1 at 0:02

asked Dec 31 '18 at 22:56

lowndrul

1,16521835

edited Jan 1 at 0:02

asked Dec 31 '18 at 22:56

lowndrul

1,16521835

asked Dec 31 '18 at 22:56

lowndrul

1,16521835

asked Dec 31 '18 at 22:56

lowndrul

1,16521835

1

both approaches seem fine to me (especially if you define the function in Approach 2 beforehand rather than anonymously inline). Why try to be cleverer than that? What specific shortcomings would you like to remedy?
– Ben Bolker
Dec 31 '18 at 23:27

1

Just taking an opportunity to understand R a little better. It seemed to me that this was such a common operation that there had to be a standard, best-practices approach.
– lowndrul
Dec 31 '18 at 23:40

add a comment |

1

both approaches seem fine to me (especially if you define the function in Approach 2 beforehand rather than anonymously inline). Why try to be cleverer than that? What specific shortcomings would you like to remedy?
– Ben Bolker
Dec 31 '18 at 23:27

1

Just taking an opportunity to understand R a little better. It seemed to me that this was such a common operation that there had to be a standard, best-practices approach.
– lowndrul
Dec 31 '18 at 23:40

both approaches seem fine to me (especially if you define the function in Approach 2 beforehand rather than anonymously inline). Why try to be cleverer than that? What specific shortcomings would you like to remedy?
– Ben Bolker
Dec 31 '18 at 23:27

Just taking an opportunity to understand R a little better. It seemed to me that this was such a common operation that there had to be a standard, best-practices approach.
– lowndrul
Dec 31 '18 at 23:40

add a comment |

5 Answers
5

active

oldest

votes

Here's another one for numeric vectors:

lapply(my_list, `*`, NA) # Instead of * it could also be +, -, etc.

# $A

#  a  b  c 

# NA NA NA 

#

# $B

#  x  y 

# NA NA

More generally,

lapply(my_list, replace, TRUE, NA)

and

lapply(ret_list, ifelse, NA, NA)

edited 2 days ago

answered Dec 31 '18 at 22:58

Julius Vainora

32.7k75979

what is * called as in this context ?
– YOLO
Dec 31 '18 at 23:12

1

@YOLO, I'm not sure what you mean. The first approach is the same as lapply(my_list, function(x) x * NA), so * is the usual product, which results to NA when one of the factors is NA.
– Julius Vainora
Dec 31 '18 at 23:15

add a comment |

You can use function is.na<- in a lapply loop.

ret_list <- lapply(my_list, `is.na<-`)

ret_list

#$A

# a  b  c 

#NA NA NA 

#

#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:16

Rui Barradas

16.1k41730

add a comment |

another alternative with dplyr:

lapply(my_list, function(x) dplyr::na_if(x,x))

answered Dec 31 '18 at 23:36

Mankind_008

1,4762312

add a comment |

If the list is not restricted to one level then use rapply.

# test data modified from question

my_list2 <- list(list(A = c(a = 1, b = 2, c = 3)), B = c(x = 10, y = 20))



rapply(my_list2, function(x) replace(x, TRUE, NA), how = "list")

which can also be written as:

rapply(my_list2, replace, list = TRUE, values = NA, how = "list")

answered Jan 1 at 0:10

G. Grothendieck

145k9126231

add a comment |

Another way around

relist(replace( unlist(my_list), TRUE, NA ), skeleton = my_list)



#$A

# a  b  c 

#NA NA NA 



#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:30

989

8,91251834

add a comment |

Your Answer

StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
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: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
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');
});

Post as a guest

Name

Required, but never shown

StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53991996%2fset-all-vector-elements-to-na-in-a-list-of-vectors%23new-answer', 'question_page');
}
);

Post as a guest

Name

Required, but never shown

5 Answers
5

active

oldest

votes

5 Answers
5

active

oldest

votes

Here's another one for numeric vectors:

lapply(my_list, `*`, NA) # Instead of * it could also be +, -, etc.

# $A

#  a  b  c 

# NA NA NA 

#

# $B

#  x  y 

# NA NA

More generally,

lapply(my_list, replace, TRUE, NA)

and

lapply(ret_list, ifelse, NA, NA)

edited 2 days ago

answered Dec 31 '18 at 22:58

Julius Vainora

32.7k75979

what is * called as in this context ?
– YOLO
Dec 31 '18 at 23:12

1

@YOLO, I'm not sure what you mean. The first approach is the same as lapply(my_list, function(x) x * NA), so * is the usual product, which results to NA when one of the factors is NA.
– Julius Vainora
Dec 31 '18 at 23:15

add a comment |

Here's another one for numeric vectors:

lapply(my_list, `*`, NA) # Instead of * it could also be +, -, etc.

# $A

#  a  b  c 

# NA NA NA 

#

# $B

#  x  y 

# NA NA

More generally,

lapply(my_list, replace, TRUE, NA)

and

lapply(ret_list, ifelse, NA, NA)

edited 2 days ago

answered Dec 31 '18 at 22:58

Julius Vainora

32.7k75979

what is * called as in this context ?
– YOLO
Dec 31 '18 at 23:12

1

@YOLO, I'm not sure what you mean. The first approach is the same as lapply(my_list, function(x) x * NA), so * is the usual product, which results to NA when one of the factors is NA.
– Julius Vainora
Dec 31 '18 at 23:15

add a comment |

Here's another one for numeric vectors:

lapply(my_list, `*`, NA) # Instead of * it could also be +, -, etc.

# $A

#  a  b  c 

# NA NA NA 

#

# $B

#  x  y 

# NA NA

More generally,

lapply(my_list, replace, TRUE, NA)

and

lapply(ret_list, ifelse, NA, NA)

edited 2 days ago

answered Dec 31 '18 at 22:58

Julius Vainora

32.7k75979

Here's another one for numeric vectors:

lapply(my_list, `*`, NA) # Instead of * it could also be +, -, etc.

# $A

#  a  b  c 

# NA NA NA 

#

# $B

#  x  y 

# NA NA

More generally,

lapply(my_list, replace, TRUE, NA)

and

lapply(ret_list, ifelse, NA, NA)

edited 2 days ago

answered Dec 31 '18 at 22:58

Julius Vainora

32.7k75979

edited 2 days ago

answered Dec 31 '18 at 22:58

Julius Vainora

32.7k75979

answered Dec 31 '18 at 22:58

Julius Vainora

32.7k75979

answered Dec 31 '18 at 22:58

Julius Vainora

32.7k75979

what is * called as in this context ?
– YOLO
Dec 31 '18 at 23:12

1

@YOLO, I'm not sure what you mean. The first approach is the same as lapply(my_list, function(x) x * NA), so * is the usual product, which results to NA when one of the factors is NA.
– Julius Vainora
Dec 31 '18 at 23:15

add a comment |

what is * called as in this context ?
– YOLO
Dec 31 '18 at 23:12

1

@YOLO, I'm not sure what you mean. The first approach is the same as lapply(my_list, function(x) x * NA), so * is the usual product, which results to NA when one of the factors is NA.
– Julius Vainora
Dec 31 '18 at 23:15

what is * called as in this context ?
– YOLO
Dec 31 '18 at 23:12

@YOLO, I'm not sure what you mean. The first approach is the same as lapply(my_list, function(x) x * NA), so * is the usual product, which results to NA when one of the factors is NA.
– Julius Vainora
Dec 31 '18 at 23:15

add a comment |

You can use function is.na<- in a lapply loop.

ret_list <- lapply(my_list, `is.na<-`)

ret_list

#$A

# a  b  c 

#NA NA NA 

#

#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:16

Rui Barradas

16.1k41730

add a comment |

You can use function is.na<- in a lapply loop.

ret_list <- lapply(my_list, `is.na<-`)

ret_list

#$A

# a  b  c 

#NA NA NA 

#

#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:16

Rui Barradas

16.1k41730

add a comment |

You can use function is.na<- in a lapply loop.

ret_list <- lapply(my_list, `is.na<-`)

ret_list

#$A

# a  b  c 

#NA NA NA 

#

#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:16

Rui Barradas

16.1k41730

You can use function is.na<- in a lapply loop.

ret_list <- lapply(my_list, `is.na<-`)

ret_list

#$A

# a  b  c 

#NA NA NA 

#

#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:16

Rui Barradas

16.1k41730

answered Dec 31 '18 at 23:16

Rui Barradas

16.1k41730

answered Dec 31 '18 at 23:16

Rui Barradas

16.1k41730

answered Dec 31 '18 at 23:16

Rui Barradas

16.1k41730

add a comment |

another alternative with dplyr:

lapply(my_list, function(x) dplyr::na_if(x,x))

answered Dec 31 '18 at 23:36

Mankind_008

1,4762312

add a comment |

another alternative with dplyr:

lapply(my_list, function(x) dplyr::na_if(x,x))

answered Dec 31 '18 at 23:36

Mankind_008

1,4762312

add a comment |

another alternative with dplyr:

lapply(my_list, function(x) dplyr::na_if(x,x))

answered Dec 31 '18 at 23:36

Mankind_008

1,4762312

another alternative with dplyr:

lapply(my_list, function(x) dplyr::na_if(x,x))

answered Dec 31 '18 at 23:36

Mankind_008

1,4762312

answered Dec 31 '18 at 23:36

Mankind_008

1,4762312

answered Dec 31 '18 at 23:36

Mankind_008

1,4762312

answered Dec 31 '18 at 23:36

Mankind_008

1,4762312

add a comment |

If the list is not restricted to one level then use rapply.

# test data modified from question

my_list2 <- list(list(A = c(a = 1, b = 2, c = 3)), B = c(x = 10, y = 20))



rapply(my_list2, function(x) replace(x, TRUE, NA), how = "list")

which can also be written as:

rapply(my_list2, replace, list = TRUE, values = NA, how = "list")

answered Jan 1 at 0:10

G. Grothendieck

145k9126231

add a comment |

If the list is not restricted to one level then use rapply.

# test data modified from question

my_list2 <- list(list(A = c(a = 1, b = 2, c = 3)), B = c(x = 10, y = 20))



rapply(my_list2, function(x) replace(x, TRUE, NA), how = "list")

which can also be written as:

rapply(my_list2, replace, list = TRUE, values = NA, how = "list")

answered Jan 1 at 0:10

G. Grothendieck

145k9126231

add a comment |

If the list is not restricted to one level then use rapply.

# test data modified from question

my_list2 <- list(list(A = c(a = 1, b = 2, c = 3)), B = c(x = 10, y = 20))



rapply(my_list2, function(x) replace(x, TRUE, NA), how = "list")

which can also be written as:

rapply(my_list2, replace, list = TRUE, values = NA, how = "list")

answered Jan 1 at 0:10

G. Grothendieck

145k9126231

If the list is not restricted to one level then use rapply.

# test data modified from question

my_list2 <- list(list(A = c(a = 1, b = 2, c = 3)), B = c(x = 10, y = 20))



rapply(my_list2, function(x) replace(x, TRUE, NA), how = "list")

which can also be written as:

rapply(my_list2, replace, list = TRUE, values = NA, how = "list")

answered Jan 1 at 0:10

G. Grothendieck

145k9126231

answered Jan 1 at 0:10

G. Grothendieck

145k9126231

answered Jan 1 at 0:10

G. Grothendieck

145k9126231

answered Jan 1 at 0:10

G. Grothendieck

145k9126231

add a comment |

Another way around

relist(replace( unlist(my_list), TRUE, NA ), skeleton = my_list)



#$A

# a  b  c 

#NA NA NA 



#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:30

989

8,91251834

add a comment |

Another way around

relist(replace( unlist(my_list), TRUE, NA ), skeleton = my_list)



#$A

# a  b  c 

#NA NA NA 



#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:30

989

8,91251834

add a comment |

Another way around

relist(replace( unlist(my_list), TRUE, NA ), skeleton = my_list)



#$A

# a  b  c 

#NA NA NA 



#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:30

989

8,91251834

Another way around

relist(replace( unlist(my_list), TRUE, NA ), skeleton = my_list)



#$A

# a  b  c 

#NA NA NA 



#$B

# x  y 

#NA NA

answered Dec 31 '18 at 23:30

989

8,91251834

answered Dec 31 '18 at 23:30

989

8,91251834

answered Dec 31 '18 at 23:30

989

8,91251834

answered Dec 31 '18 at 23:30

989

8,91251834

add a comment |

draft saved

draft discarded

Thanks for contributing an answer to Stack Overflow!

Please be sure to answer the question. Provide details and share your research!

But avoid …

Asking for help, clarification, or responding to other answers.

Making statements based on opinion; back them up with references or personal experience.

To learn more, see our tips on writing great answers.

Some of your past answers have not been well-received, and you're in danger of being blocked from answering.

Please pay close attention to the following guidance:

Please be sure to answer the question. Provide details and share your research!

But avoid …

Asking for help, clarification, or responding to other answers.

Making statements based on opinion; back them up with references or personal experience.

To learn more, see our tips on writing great answers.

draft saved

draft discarded

Sign up or log in

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

Post as a guest

Name

Required, but never shown

Post as a guest

Name

Required, but never shown

Sign up or log in

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

Post as a guest

Name

Required, but never shown

Sign up or log in

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

Post as a guest

Name

Required, but never shown

Sign up or log in

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

Post as a guest

Name

Required, but never shown

Name

Required, but never shown

Name

Required, but never shown

This page is only for reference, If you need detailed information, please check here

搜尋此網誌

Argthtjtr