What's the difference between using select + unlist from dplyr package and using the dollar sign?

I've been taking an online course in which the instructor always does the following to obtain, say, the column Col1 from a data.frame object Dat:

library(dplyr)

unlist(select(Dat, Col1))

Why not simply run Dat$Col1? I notice a difference in the "presentation" of both results, but is there any other significant divergence between the two forms? Any operation will result in the same product for both?

edited yesterday

Ben Bolker

132k11222309

asked yesterday

G. Monteiro

513

New contributor

8

Your instructor is probably just a fan of the tidyverse. Dat$Col1 is my preferred method for getting a column.
– Rich Scriven
yesterday

9

...but not well-versed enough to know of pull.
– Henrik
yesterday

4

Touche. Maybe OP can take the instructor to school.
– Rich Scriven
yesterday

3

Wow, he loads an entire new library for that?
– cory
yesterday

5

The rumours about the SO incident spread, and the instructor decided to gather every student. today he had started to select cigarettes without filter, and took a long, deep pull to compose himself for a minute. It was a mare’s nest. “Well, I have a crow to pluck with you, who did this?”, the teacher started. "between you and me: this is no funs. You better not cross me, or I will reduce your grades, every grade. Whichever way you slice it - period!" The students looked at each other. A complete farce. Happy new year every one - tally-ho!
– Henrik
yesterday

|
show 1 more comment

I've been taking an online course in which the instructor always does the following to obtain, say, the column Col1 from a data.frame object Dat:

library(dplyr)

unlist(select(Dat, Col1))

edited yesterday

Ben Bolker

132k11222309

asked yesterday

G. Monteiro

513

New contributor

8

Your instructor is probably just a fan of the tidyverse. Dat$Col1 is my preferred method for getting a column.
– Rich Scriven
yesterday

9

...but not well-versed enough to know of pull.
– Henrik
yesterday

4

Touche. Maybe OP can take the instructor to school.
– Rich Scriven
yesterday

3

Wow, he loads an entire new library for that?
– cory
yesterday

5

The rumours about the SO incident spread, and the instructor decided to gather every student. today he had started to select cigarettes without filter, and took a long, deep pull to compose himself for a minute. It was a mare’s nest. “Well, I have a crow to pluck with you, who did this?”, the teacher started. "between you and me: this is no funs. You better not cross me, or I will reduce your grades, every grade. Whichever way you slice it - period!" The students looked at each other. A complete farce. Happy new year every one - tally-ho!
– Henrik
yesterday

|
show 1 more comment

I've been taking an online course in which the instructor always does the following to obtain, say, the column Col1 from a data.frame object Dat:

library(dplyr)

unlist(select(Dat, Col1))

edited yesterday

Ben Bolker

132k11222309

asked yesterday

G. Monteiro

513

New contributor

I've been taking an online course in which the instructor always does the following to obtain, say, the column Col1 from a data.frame object Dat:

library(dplyr)

unlist(select(Dat, Col1))

r dplyr

edited yesterday

Ben Bolker

132k11222309

asked yesterday

G. Monteiro

513

New contributor

edited yesterday

Ben Bolker

132k11222309

asked yesterday

G. Monteiro

513

New contributor

edited yesterday

Ben Bolker

132k11222309

edited yesterday

Ben Bolker

132k11222309

edited yesterday

Ben Bolker

132k11222309

asked yesterday

G. Monteiro

513

New contributor

asked yesterday

G. Monteiro

513

asked yesterday

G. Monteiro

513

New contributor

G. Monteiro is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

8

Your instructor is probably just a fan of the tidyverse. Dat$Col1 is my preferred method for getting a column.
– Rich Scriven
yesterday

9

...but not well-versed enough to know of pull.
– Henrik
yesterday

4

Touche. Maybe OP can take the instructor to school.
– Rich Scriven
yesterday

3

Wow, he loads an entire new library for that?
– cory
yesterday

5

The rumours about the SO incident spread, and the instructor decided to gather every student. today he had started to select cigarettes without filter, and took a long, deep pull to compose himself for a minute. It was a mare’s nest. “Well, I have a crow to pluck with you, who did this?”, the teacher started. "between you and me: this is no funs. You better not cross me, or I will reduce your grades, every grade. Whichever way you slice it - period!" The students looked at each other. A complete farce. Happy new year every one - tally-ho!
– Henrik
yesterday

|
show 1 more comment

8

Your instructor is probably just a fan of the tidyverse. Dat$Col1 is my preferred method for getting a column.
– Rich Scriven
yesterday

9

...but not well-versed enough to know of pull.
– Henrik
yesterday

4

Touche. Maybe OP can take the instructor to school.
– Rich Scriven
yesterday

3

Wow, he loads an entire new library for that?
– cory
yesterday

5

The rumours about the SO incident spread, and the instructor decided to gather every student. today he had started to select cigarettes without filter, and took a long, deep pull to compose himself for a minute. It was a mare’s nest. “Well, I have a crow to pluck with you, who did this?”, the teacher started. "between you and me: this is no funs. You better not cross me, or I will reduce your grades, every grade. Whichever way you slice it - period!" The students looked at each other. A complete farce. Happy new year every one - tally-ho!
– Henrik
yesterday

Your instructor is probably just a fan of the tidyverse. Dat$Col1 is my preferred method for getting a column.
– Rich Scriven
yesterday

...but not well-versed enough to know of pull.
– Henrik
yesterday

Touche. Maybe OP can take the instructor to school.
– Rich Scriven
yesterday

Wow, he loads an entire new library for that?
– cory
yesterday

The rumours about the SO incident spread, and the instructor decided to gather every student. today he had started to select cigarettes without filter, and took a long, deep pull to compose himself for a minute. It was a mare’s nest. “Well, I have a crow to pluck with you, who did this?”, the teacher started. "between you and me: this is no funs. You better not cross me, or I will reduce your grades, every grade. Whichever way you slice it - period!" The students looked at each other. A complete farce. Happy new year every one - tally-ho!
– Henrik
yesterday

|
show 1 more comment

1 Answer
1

active

oldest

votes

(Posting comments as community wiki.)

These are not quite equivalent - unlist(select(.)) keeps (probably unwanted) names.

dd <- data.frame(Col1=c("abc","def"))

str(unlist(select(dd,Col1)))

##  Factor w/ 2 levels "abc","def": 1 2

##  - attr(*, "names")= chr [1:2] "Col11" "Col12"

str(dd$Col1)

##  Factor w/ 2 levels "abc","def": 1 2

Your instructor is probably just a fan of the tidyverse (@RichScriven); pull(Dat, Col1) or (for extreme "tidiness") Dat %>% pull(Col1) would be more idiomatic (@Henrik). Dat$Col1 or Dat[["Col1"]] would be the base-R equivalents (the former is more convenient for interactive use, the latter is marginally safer for programming purposes since it won't do name-completion).

It hardly matters, but the tidyverse approaches are much slower.

microbenchmark(dd$Col1,dd[["Col1"]],pull(dd,Col1),unlist(select(dd,Col1)))

Unit: microseconds

                     expr     min        lq       mean    median       uq

                  dd$Col1   5.296   10.9630   14.86871   13.4040   17.160

             dd[["Col1"]]   7.870    9.6535   15.18874   11.8270   16.635

           pull(dd, Col1)  44.160  108.7625  128.89342  117.8415  136.890

 unlist(select(dd, Col1)) 601.480 1132.8240 1436.44178 1214.4420 1378.141

      max neval cld

   31.036   100  a 

   88.842   100  a 

  422.462   100  a 

 8796.964   100   b

edited yesterday

community wiki

2 revs
Ben Bolker

2

Since you mentioned it, pull(dd, Col1) is twice as fast as dd %>% pull(Col1). Tested with a much larger dd <- data.frame(Col1 = sample(c("abc", "def"), 1e6, TRUE)).
– Rui Barradas
yesterday

1

Just to note, there's always the use.names argument to the base R function, unlist which will drop any unwanted names: unlist(select(.), use.names=FALSE).
– lmo
yesterday

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
});

}
});

G. Monteiro is a new contributor. Be nice, and check out our Code of Conduct.

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%2f54056096%2fwhats-the-difference-between-using-select-unlist-from-dplyr-package-and-using%23new-answer', 'question_page');
}
);

Post as a guest

Name

Required, but never shown

1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

(Posting comments as community wiki.)

These are not quite equivalent - unlist(select(.)) keeps (probably unwanted) names.

dd <- data.frame(Col1=c("abc","def"))

str(unlist(select(dd,Col1)))

##  Factor w/ 2 levels "abc","def": 1 2

##  - attr(*, "names")= chr [1:2] "Col11" "Col12"

str(dd$Col1)

##  Factor w/ 2 levels "abc","def": 1 2

It hardly matters, but the tidyverse approaches are much slower.

microbenchmark(dd$Col1,dd[["Col1"]],pull(dd,Col1),unlist(select(dd,Col1)))

Unit: microseconds

                     expr     min        lq       mean    median       uq

                  dd$Col1   5.296   10.9630   14.86871   13.4040   17.160

             dd[["Col1"]]   7.870    9.6535   15.18874   11.8270   16.635

           pull(dd, Col1)  44.160  108.7625  128.89342  117.8415  136.890

 unlist(select(dd, Col1)) 601.480 1132.8240 1436.44178 1214.4420 1378.141

      max neval cld

   31.036   100  a 

   88.842   100  a 

  422.462   100  a 

 8796.964   100   b

edited yesterday

community wiki

2 revs
Ben Bolker

2

Since you mentioned it, pull(dd, Col1) is twice as fast as dd %>% pull(Col1). Tested with a much larger dd <- data.frame(Col1 = sample(c("abc", "def"), 1e6, TRUE)).
– Rui Barradas
yesterday

1

Just to note, there's always the use.names argument to the base R function, unlist which will drop any unwanted names: unlist(select(.), use.names=FALSE).
– lmo
yesterday

add a comment |

(Posting comments as community wiki.)

These are not quite equivalent - unlist(select(.)) keeps (probably unwanted) names.

dd <- data.frame(Col1=c("abc","def"))

str(unlist(select(dd,Col1)))

##  Factor w/ 2 levels "abc","def": 1 2

##  - attr(*, "names")= chr [1:2] "Col11" "Col12"

str(dd$Col1)

##  Factor w/ 2 levels "abc","def": 1 2

It hardly matters, but the tidyverse approaches are much slower.

microbenchmark(dd$Col1,dd[["Col1"]],pull(dd,Col1),unlist(select(dd,Col1)))

Unit: microseconds

                     expr     min        lq       mean    median       uq

                  dd$Col1   5.296   10.9630   14.86871   13.4040   17.160

             dd[["Col1"]]   7.870    9.6535   15.18874   11.8270   16.635

           pull(dd, Col1)  44.160  108.7625  128.89342  117.8415  136.890

 unlist(select(dd, Col1)) 601.480 1132.8240 1436.44178 1214.4420 1378.141

      max neval cld

   31.036   100  a 

   88.842   100  a 

  422.462   100  a 

 8796.964   100   b

edited yesterday

community wiki

2 revs
Ben Bolker

2

Since you mentioned it, pull(dd, Col1) is twice as fast as dd %>% pull(Col1). Tested with a much larger dd <- data.frame(Col1 = sample(c("abc", "def"), 1e6, TRUE)).
– Rui Barradas
yesterday

1

Just to note, there's always the use.names argument to the base R function, unlist which will drop any unwanted names: unlist(select(.), use.names=FALSE).
– lmo
yesterday

add a comment |

(Posting comments as community wiki.)

These are not quite equivalent - unlist(select(.)) keeps (probably unwanted) names.

dd <- data.frame(Col1=c("abc","def"))

str(unlist(select(dd,Col1)))

##  Factor w/ 2 levels "abc","def": 1 2

##  - attr(*, "names")= chr [1:2] "Col11" "Col12"

str(dd$Col1)

##  Factor w/ 2 levels "abc","def": 1 2

It hardly matters, but the tidyverse approaches are much slower.

microbenchmark(dd$Col1,dd[["Col1"]],pull(dd,Col1),unlist(select(dd,Col1)))

Unit: microseconds

                     expr     min        lq       mean    median       uq

                  dd$Col1   5.296   10.9630   14.86871   13.4040   17.160

             dd[["Col1"]]   7.870    9.6535   15.18874   11.8270   16.635

           pull(dd, Col1)  44.160  108.7625  128.89342  117.8415  136.890

 unlist(select(dd, Col1)) 601.480 1132.8240 1436.44178 1214.4420 1378.141

      max neval cld

   31.036   100  a 

   88.842   100  a 

  422.462   100  a 

 8796.964   100   b

edited yesterday

community wiki

2 revs
Ben Bolker

(Posting comments as community wiki.)

These are not quite equivalent - unlist(select(.)) keeps (probably unwanted) names.

dd <- data.frame(Col1=c("abc","def"))

str(unlist(select(dd,Col1)))

##  Factor w/ 2 levels "abc","def": 1 2

##  - attr(*, "names")= chr [1:2] "Col11" "Col12"

str(dd$Col1)

##  Factor w/ 2 levels "abc","def": 1 2

It hardly matters, but the tidyverse approaches are much slower.

microbenchmark(dd$Col1,dd[["Col1"]],pull(dd,Col1),unlist(select(dd,Col1)))

Unit: microseconds

                     expr     min        lq       mean    median       uq

                  dd$Col1   5.296   10.9630   14.86871   13.4040   17.160

             dd[["Col1"]]   7.870    9.6535   15.18874   11.8270   16.635

           pull(dd, Col1)  44.160  108.7625  128.89342  117.8415  136.890

 unlist(select(dd, Col1)) 601.480 1132.8240 1436.44178 1214.4420 1378.141

      max neval cld

   31.036   100  a 

   88.842   100  a 

  422.462   100  a 

 8796.964   100   b

edited yesterday

community wiki

2 revs
Ben Bolker

edited yesterday

community wiki

2 revs
Ben Bolker

community wiki

2 revs
Ben Bolker

community wiki

2 revs
Ben Bolker

2

Since you mentioned it, pull(dd, Col1) is twice as fast as dd %>% pull(Col1). Tested with a much larger dd <- data.frame(Col1 = sample(c("abc", "def"), 1e6, TRUE)).
– Rui Barradas
yesterday

1

Just to note, there's always the use.names argument to the base R function, unlist which will drop any unwanted names: unlist(select(.), use.names=FALSE).
– lmo
yesterday

add a comment |

2

Since you mentioned it, pull(dd, Col1) is twice as fast as dd %>% pull(Col1). Tested with a much larger dd <- data.frame(Col1 = sample(c("abc", "def"), 1e6, TRUE)).
– Rui Barradas
yesterday

1

Just to note, there's always the use.names argument to the base R function, unlist which will drop any unwanted names: unlist(select(.), use.names=FALSE).
– lmo
yesterday

Since you mentioned it, pull(dd, Col1) is twice as fast as dd %>% pull(Col1). Tested with a much larger dd <- data.frame(Col1 = sample(c("abc", "def"), 1e6, TRUE)).
– Rui Barradas
yesterday

Just to note, there's always the use.names argument to the base R function, unlist which will drop any unwanted names: unlist(select(.), use.names=FALSE).
– lmo
yesterday

add a comment |

G. Monteiro is a new contributor. Be nice, and check out our Code of Conduct.

draft saved

draft discarded

G. Monteiro is a new contributor. Be nice, and check out our Code of Conduct.

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

Mfrhtyj