Re: [R] When using require(), why do I get the error message "Error in if (!loaded) { : the condition has length > 1" ?
Andrew,
Thanks. I reviewed the code for "require" and saw:
"if (!character.only)
package <- as.character(substitute(package))"
#This helps me better understand what is going on. I am sharing this
here because I think it might help others understand.
as.character( substitute("this_pac_does_not_exist") ) #quoted
as.character( substitute( this_pac_does_not_exist ) ) #not quoted
as.character( substitute("this_pac_does_not_exist") ) == as.character(
substitute( this_pac_does_not_exist ) )
#
packages_i_want_to_use <- c("this_pac_does_not_exist", "abcz")
as.character( substitute(packages_i_want_to_use[1] ) )
packages_i_want_to_use[1]
as.character( substitute(packages_i_want_to_use[1] ) ) ==
packages_i_want_to_use[1]
#To prevent substitute(packages_i_want_to_use[1] from getting changed
to as.character( substitute(packages_i_want_to_use[1] ) ), we need to
set character.only = TRUE
On Mon, Oct 24, 2022 at 12:53 PM Andrew Simmons wrote:
>
> In the first one, the argument is a character vector of length 1, so the code
> works perfectly fine.
>
> The second is a call, and when coerced to a character vector should look like
>
> c("[", "packages_i_want_to_use", "1")
>
> You can try this yourself with quote(packages_i_want_to_use[1]) which returns
> its first argument, unevaluated.
>
> On Mon, Oct 24, 2022, 12:46 Kelly Thompson wrote:
>>
>> Thanks!
>>
>> # Please, can you help me understand why
>> require( 'base' ) # works, but
>> require( packages_i_want_to_use[1] ) # does not work?
>>
>> # In require( 'base' ), what is the "first argument"?
>>
>> On Mon, Oct 24, 2022 at 12:29 PM Andrew Simmons wrote:
>> >
>> > require(), similarly to library(), does not evaluate its first argument
>> > UNLESS you add character.only = TRUE
>> >
>> > require( packages_i_want_to_use[1], character.only = TRUE)
>> >
>> >
>> > On Mon, Oct 24, 2022, 12:26 Kelly Thompson wrote:
>> >>
>> >> # Below, when using require(), why do I get the error message "Error
>> >> in if (!loaded) { : the condition has length > 1" ?
>> >>
>> >> # This is my reproducible code:
>> >>
>> >> #create a vector with the names of the packages I want to use
>> >> packages_i_want_to_use <- c('base', 'this_pac_does_not_exist')
>> >>
>> >> # Here I get error messages:
>> >> require( packages_i_want_to_use[1] )
>> >> #Error in if (!loaded) { : the condition has length > 1
>> >>
>> >> require( packages_i_want_to_use[2] )
>> >> #Error in if (!loaded) { : the condition has length > 1
>> >>
>> >> # Here I get what I expect:
>> >> require('base')
>> >>
>> >> require('this_pac_does_not_exist')
>> >> #Loading required package: this_pac_does_not_exist
>> >> #Warning message:
>> >> #In library(package, lib.loc = lib.loc, character.only = TRUE,
>> >> logical.return = TRUE, :
>> >> # there is no package called ‘this_pac_does_not_exist’
>> >>
>> >> __
>> >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> >> https://stat.ethz.ch/mailman/listinfo/r-help
>> >> PLEASE do read the posting guide
>> >> http://www.R-project.org/posting-guide.html
>> >> and provide commented, minimal, self-contained, reproducible code.
>>
>> __
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
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Re: [R] When using require(), why do I get the error message "Error in if (!loaded) { : the condition has length > 1" ?
In the first one, the argument is a character vector of length 1, so the
code works perfectly fine.
The second is a call, and when coerced to a character vector should look
like
c("[", "packages_i_want_to_use", "1")
You can try this yourself with quote(packages_i_want_to_use[1]) which
returns its first argument, unevaluated.
On Mon, Oct 24, 2022, 12:46 Kelly Thompson wrote:
> Thanks!
>
> # Please, can you help me understand why
> require( 'base' ) # works, but
> require( packages_i_want_to_use[1] ) # does not work?
>
> # In require( 'base' ), what is the "first argument"?
>
> On Mon, Oct 24, 2022 at 12:29 PM Andrew Simmons
> wrote:
> >
> > require(), similarly to library(), does not evaluate its first argument
> UNLESS you add character.only = TRUE
> >
> > require( packages_i_want_to_use[1], character.only = TRUE)
> >
> >
> > On Mon, Oct 24, 2022, 12:26 Kelly Thompson wrote:
> >>
> >> # Below, when using require(), why do I get the error message "Error
> >> in if (!loaded) { : the condition has length > 1" ?
> >>
> >> # This is my reproducible code:
> >>
> >> #create a vector with the names of the packages I want to use
> >> packages_i_want_to_use <- c('base', 'this_pac_does_not_exist')
> >>
> >> # Here I get error messages:
> >> require( packages_i_want_to_use[1] )
> >> #Error in if (!loaded) { : the condition has length > 1
> >>
> >> require( packages_i_want_to_use[2] )
> >> #Error in if (!loaded) { : the condition has length > 1
> >>
> >> # Here I get what I expect:
> >> require('base')
> >>
> >> require('this_pac_does_not_exist')
> >> #Loading required package: this_pac_does_not_exist
> >> #Warning message:
> >> #In library(package, lib.loc = lib.loc, character.only = TRUE,
> >> logical.return = TRUE, :
> >> # there is no package called ‘this_pac_does_not_exist’
> >>
> >> __
> >> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> >> https://stat.ethz.ch/mailman/listinfo/r-help
> >> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> >> and provide commented, minimal, self-contained, reproducible code.
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
[[alternative HTML version deleted]]
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] When using require(), why do I get the error message "Error in if (!loaded) { : the condition has length > 1" ?
Thanks!
# Please, can you help me understand why
require( 'base' ) # works, but
require( packages_i_want_to_use[1] ) # does not work?
# In require( 'base' ), what is the "first argument"?
On Mon, Oct 24, 2022 at 12:29 PM Andrew Simmons wrote:
>
> require(), similarly to library(), does not evaluate its first argument
> UNLESS you add character.only = TRUE
>
> require( packages_i_want_to_use[1], character.only = TRUE)
>
>
> On Mon, Oct 24, 2022, 12:26 Kelly Thompson wrote:
>>
>> # Below, when using require(), why do I get the error message "Error
>> in if (!loaded) { : the condition has length > 1" ?
>>
>> # This is my reproducible code:
>>
>> #create a vector with the names of the packages I want to use
>> packages_i_want_to_use <- c('base', 'this_pac_does_not_exist')
>>
>> # Here I get error messages:
>> require( packages_i_want_to_use[1] )
>> #Error in if (!loaded) { : the condition has length > 1
>>
>> require( packages_i_want_to_use[2] )
>> #Error in if (!loaded) { : the condition has length > 1
>>
>> # Here I get what I expect:
>> require('base')
>>
>> require('this_pac_does_not_exist')
>> #Loading required package: this_pac_does_not_exist
>> #Warning message:
>> #In library(package, lib.loc = lib.loc, character.only = TRUE,
>> logical.return = TRUE, :
>> # there is no package called ‘this_pac_does_not_exist’
>>
>> __
>> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] When using require(), why do I get the error message "Error in if (!loaded) { : the condition has length > 1" ?
Don't load base. It is already loaded.
On October 24, 2022 9:07:44 AM PDT, Kelly Thompson wrote:
># Below, when using require(), why do I get the error message "Error
>in if (!loaded) { : the condition has length > 1" ?
>
># This is my reproducible code:
>
>#create a vector with the names of the packages I want to use
>packages_i_want_to_use <- c('base', 'this_pac_does_not_exist')
>
># Here I get error messages:
>require( packages_i_want_to_use[1] )
>#Error in if (!loaded) { : the condition has length > 1
>
>require( packages_i_want_to_use[2] )
>#Error in if (!loaded) { : the condition has length > 1
>
># Here I get what I expect:
>require('base')
>
>require('this_pac_does_not_exist')
>#Loading required package: this_pac_does_not_exist
>#Warning message:
>#In library(package, lib.loc = lib.loc, character.only = TRUE,
>logical.return = TRUE, :
># there is no package called ‘this_pac_does_not_exist’
>
>__
>R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.
--
Sent from my phone. Please excuse my brevity.
__
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] When using require(), why do I get the error message "Error in if (!loaded) { : the condition has length > 1" ?
Reread ?require more carefully. Especially for the 'package' argument.
Incidentally, you don't need to require base. It's always available.
-- Bert
On Mon, Oct 24, 2022 at 9:25 AM Kelly Thompson wrote:
>
> # Below, when using require(), why do I get the error message "Error
> in if (!loaded) { : the condition has length > 1" ?
>
> # This is my reproducible code:
>
> #create a vector with the names of the packages I want to use
> packages_i_want_to_use <- c('base', 'this_pac_does_not_exist')
>
> # Here I get error messages:
> require( packages_i_want_to_use[1] )
> #Error in if (!loaded) { : the condition has length > 1
>
> require( packages_i_want_to_use[2] )
> #Error in if (!loaded) { : the condition has length > 1
>
> # Here I get what I expect:
> require('base')
>
> require('this_pac_does_not_exist')
> #Loading required package: this_pac_does_not_exist
> #Warning message:
> #In library(package, lib.loc = lib.loc, character.only = TRUE,
> logical.return = TRUE, :
> # there is no package called ‘this_pac_does_not_exist’
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] When using require(), why do I get the error message "Error in if (!loaded) { : the condition has length > 1" ?
You need to pass character.only = TRUE to require() whenever you
specify the package using a character variable.
I agree, the error message is confusing.
/Henrik
On Mon, Oct 24, 2022 at 9:26 AM Kelly Thompson wrote:
>
> # Below, when using require(), why do I get the error message "Error
> in if (!loaded) { : the condition has length > 1" ?
>
> # This is my reproducible code:
>
> #create a vector with the names of the packages I want to use
> packages_i_want_to_use <- c('base', 'this_pac_does_not_exist')
>
> # Here I get error messages:
> require( packages_i_want_to_use[1] )
> #Error in if (!loaded) { : the condition has length > 1
>
> require( packages_i_want_to_use[2] )
> #Error in if (!loaded) { : the condition has length > 1
>
> # Here I get what I expect:
> require('base')
>
> require('this_pac_does_not_exist')
> #Loading required package: this_pac_does_not_exist
> #Warning message:
> #In library(package, lib.loc = lib.loc, character.only = TRUE,
> logical.return = TRUE, :
> # there is no package called ‘this_pac_does_not_exist’
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
__
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
Re: [R] When using require(), why do I get the error message "Error in if (!loaded) { : the condition has length > 1" ?
require(), similarly to library(), does not evaluate its first argument
UNLESS you add character.only = TRUE
require( packages_i_want_to_use[1], character.only = TRUE)
On Mon, Oct 24, 2022, 12:26 Kelly Thompson wrote:
> # Below, when using require(), why do I get the error message "Error
> in if (!loaded) { : the condition has length > 1" ?
>
> # This is my reproducible code:
>
> #create a vector with the names of the packages I want to use
> packages_i_want_to_use <- c('base', 'this_pac_does_not_exist')
>
> # Here I get error messages:
> require( packages_i_want_to_use[1] )
> #Error in if (!loaded) { : the condition has length > 1
>
> require( packages_i_want_to_use[2] )
> #Error in if (!loaded) { : the condition has length > 1
>
> # Here I get what I expect:
> require('base')
>
> require('this_pac_does_not_exist')
> #Loading required package: this_pac_does_not_exist
> #Warning message:
> #In library(package, lib.loc = lib.loc, character.only = TRUE,
> logical.return = TRUE, :
> # there is no package called ‘this_pac_does_not_exist’
>
> __
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
[[alternative HTML version deleted]]
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and provide commented, minimal, self-contained, reproducible code.
Re: [R] When using require(), why do I get the error message "Error in if (!loaded) { : the condition has length > 1" ?
В Mon, 24 Oct 2022 12:07:44 -0400
Kelly Thompson пишет:
> require( packages_i_want_to_use[1] )
> #Error in if (!loaded) { : the condition has length > 1
This seems to be a bug in require(). In addition to understanding
character strings as arguments, require() can load packages named by
unquoted barewords:
require(base)
This uses non-standard evaluation, and the part that transforms an
unquoted symbol into a package name doesn't expect to see what is
effectively `[`(packages_i_want_to_use, 1) instead of a single symbol.
If you pass the character.only = TRUE argument to require(), this
additional handling is disabled, making your examples work again. It's
a good idea to always pass this argument when calling require() with a
variable as the first argument.
--
Best regards,
Ivan
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