Mixing
readr: Passing a string of column classes
I want to use readr::read_csv() to read several data sets.
I have a CSV with the description of each file that looks like this:
# A tibble: 5 x 8
Object_Name File_Path Column1 Column2 Column3 Column4 Column5 Column6
<chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr>
1 Object1 data/file1.csv character character character numeric numeric numeric
2 Object2 data/file2.csv character character character numeric NA NA
3 Object3 data/file3.csv character character numeric NA NA NA
4 Object4 data/file4.csv character numeric numeric numeric NA NA
5 Object5 data/file5.csv character numeric numeric NA NA NA
What I wish if for something like this to work:
for (i in 1:nrow(list_of_files)) {
obj_name <- list_of_files[i,]$Object_Name
pth <- list_of_files[i,]$File_Path
col_types <- as.character(list_of_files[i,3:8])
col_types <- col_types[!is.na(col_types)]
# This part doesnt work
tab <- readr::read_csv(file = pth,
col_types = col_types)
assign(obj_name,tab)
}
Usually the guessing works, but I need to make sure.
EDIT
Simplifying the questions, so maybe it's clearer.
To specify the columns types on read_csv, you need a cols() call.
This works:
> cols('c', 'n')
cols(
= col_character(),
= col_number()
)
This doesn't work:
> aa <- c('c','n')
> cols(aa)
Error in switch(x, `_` = , `-` = col_skip(), `?` = col_guess(), c = col_character(), :
EXPR must be a length 1 vector
Because I'm iterating through a bunch of files, I need something that looks like the second example. I can save somewhere a string with the columns specifications, but how do I turn a string into a cols() object?
r readr
asked Nov 16 '18 at 23:10
Leo BarlachLeo Barlach
384
add a comment |
I want to use readr::read_csv() to read several data sets.
I have a CSV with the description of each file that looks like this:
# A tibble: 5 x 8
Object_Name File_Path Column1 Column2 Column3 Column4 Column5 Column6
<chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr>
1 Object1 data/file1.csv character character character numeric numeric numeric
2 Object2 data/file2.csv character character character numeric NA NA
3 Object3 data/file3.csv character character numeric NA NA NA
4 Object4 data/file4.csv character numeric numeric numeric NA NA
5 Object5 data/file5.csv character numeric numeric NA NA NA
What I wish if for something like this to work:
for (i in 1:nrow(list_of_files)) {
obj_name <- list_of_files[i,]$Object_Name
pth <- list_of_files[i,]$File_Path
col_types <- as.character(list_of_files[i,3:8])
col_types <- col_types[!is.na(col_types)]
# This part doesnt work
tab <- readr::read_csv(file = pth,
col_types = col_types)
assign(obj_name,tab)
}
Usually the guessing works, but I need to make sure.
EDIT
Simplifying the questions, so maybe it's clearer.
To specify the columns types on read_csv, you need a cols() call.
This works:
> cols('c', 'n')
cols(
= col_character(),
= col_number()
)
This doesn't work:
> aa <- c('c','n')
> cols(aa)
Error in switch(x, `_` = , `-` = col_skip(), `?` = col_guess(), c = col_character(), :
EXPR must be a length 1 vector
Because I'm iterating through a bunch of files, I need something that looks like the second example. I can save somewhere a string with the columns specifications, but how do I turn a string into a cols() object?
r readr
asked Nov 16 '18 at 23:10
Leo BarlachLeo Barlach
384
Difficult to find an answer without seeing the exact error message, please edit your question to show what exactly happens ("doesn't work"). THX :-)
– R Yoda
Nov 16 '18 at 23:42
Check the documentation forread_csv; you needcol_typesargument to be "One of NULL, a cols() specification, or a string." Currently you have none of these options.
– Calum You
Nov 17 '18 at 0:18
I added more details to the question. Basically, if I have saved a string with columns specifications, how do I turn it into a cols() object?
– Leo Barlach
Nov 19 '18 at 18:13
add a comment |
I want to use readr::read_csv() to read several data sets.
I have a CSV with the description of each file that looks like this:
# A tibble: 5 x 8
Object_Name File_Path Column1 Column2 Column3 Column4 Column5 Column6
<chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr>
1 Object1 data/file1.csv character character character numeric numeric numeric
2 Object2 data/file2.csv character character character numeric NA NA
3 Object3 data/file3.csv character character numeric NA NA NA
4 Object4 data/file4.csv character numeric numeric numeric NA NA
5 Object5 data/file5.csv character numeric numeric NA NA NA
What I wish if for something like this to work:
for (i in 1:nrow(list_of_files)) {
obj_name <- list_of_files[i,]$Object_Name
pth <- list_of_files[i,]$File_Path
col_types <- as.character(list_of_files[i,3:8])
col_types <- col_types[!is.na(col_types)]
# This part doesnt work
tab <- readr::read_csv(file = pth,
col_types = col_types)
assign(obj_name,tab)
}
Usually the guessing works, but I need to make sure.
EDIT
Simplifying the questions, so maybe it's clearer.
To specify the columns types on read_csv, you need a cols() call.
This works:
> cols('c', 'n')
cols(
= col_character(),
= col_number()
)
This doesn't work:
> aa <- c('c','n')
> cols(aa)
Error in switch(x, `_` = , `-` = col_skip(), `?` = col_guess(), c = col_character(), :
EXPR must be a length 1 vector
Because I'm iterating through a bunch of files, I need something that looks like the second example. I can save somewhere a string with the columns specifications, but how do I turn a string into a cols() object?
r readr
asked Nov 16 '18 at 23:10
Leo BarlachLeo Barlach
384
I want to use readr::read_csv() to read several data sets.
I have a CSV with the description of each file that looks like this:
# A tibble: 5 x 8
Object_Name File_Path Column1 Column2 Column3 Column4 Column5 Column6
<chr> <chr> <chr> <chr> <chr> <chr> <chr> <chr>
1 Object1 data/file1.csv character character character numeric numeric numeric
2 Object2 data/file2.csv character character character numeric NA NA
3 Object3 data/file3.csv character character numeric NA NA NA
4 Object4 data/file4.csv character numeric numeric numeric NA NA
5 Object5 data/file5.csv character numeric numeric NA NA NA
What I wish if for something like this to work:
for (i in 1:nrow(list_of_files)) {
obj_name <- list_of_files[i,]$Object_Name
pth <- list_of_files[i,]$File_Path
col_types <- as.character(list_of_files[i,3:8])
col_types <- col_types[!is.na(col_types)]
# This part doesnt work
tab <- readr::read_csv(file = pth,
col_types = col_types)
assign(obj_name,tab)
}
Usually the guessing works, but I need to make sure.
EDIT
Simplifying the questions, so maybe it's clearer.
To specify the columns types on read_csv, you need a cols() call.
This works:
> cols('c', 'n')
cols(
= col_character(),
= col_number()
)
This doesn't work:
> aa <- c('c','n')
> cols(aa)
Error in switch(x, `_` = , `-` = col_skip(), `?` = col_guess(), c = col_character(), :
EXPR must be a length 1 vector
Because I'm iterating through a bunch of files, I need something that looks like the second example. I can save somewhere a string with the columns specifications, but how do I turn a string into a cols() object?
r readr
r readr
asked Nov 16 '18 at 23:10
Leo BarlachLeo Barlach
384
asked Nov 16 '18 at 23:10
Leo BarlachLeo Barlach
384
edited Nov 19 '18 at 18:12
Leo Barlach
asked Nov 16 '18 at 23:10
Leo BarlachLeo Barlach
384
asked Nov 16 '18 at 23:10
Leo BarlachLeo Barlach
384
asked Nov 16 '18 at 23:10
Leo BarlachLeo Barlach
384
384
Difficult to find an answer without seeing the exact error message, please edit your question to show what exactly happens ("doesn't work"). THX :-)
– R Yoda
Nov 16 '18 at 23:42
Check the documentation forread_csv; you needcol_typesargument to be "One of NULL, a cols() specification, or a string." Currently you have none of these options.
– Calum You
Nov 17 '18 at 0:18
I added more details to the question. Basically, if I have saved a string with columns specifications, how do I turn it into a cols() object?
– Leo Barlach
Nov 19 '18 at 18:13
add a comment |
Difficult to find an answer without seeing the exact error message, please edit your question to show what exactly happens ("doesn't work"). THX :-)
– R Yoda
Nov 16 '18 at 23:42
Check the documentation forread_csv; you needcol_typesargument to be "One of NULL, a cols() specification, or a string." Currently you have none of these options.
– Calum You
Nov 17 '18 at 0:18
I added more details to the question. Basically, if I have saved a string with columns specifications, how do I turn it into a cols() object?
– Leo Barlach
Nov 19 '18 at 18:13
Difficult to find an answer without seeing the exact error message, please edit your question to show what exactly happens ("doesn't work"). THX :-)
– R Yoda
Nov 16 '18 at 23:42
Difficult to find an answer without seeing the exact error message, please edit your question to show what exactly happens ("doesn't work"). THX :-)
– R Yoda
Nov 16 '18 at 23:42
Check the documentation for
read_csv; you need col_types argument to be "One of NULL, a cols() specification, or a string." Currently you have none of these options.– Calum You
Nov 17 '18 at 0:18
Check the documentation for
read_csv; you need col_types argument to be "One of NULL, a cols() specification, or a string." Currently you have none of these options.– Calum You
Nov 17 '18 at 0:18
I added more details to the question. Basically, if I have saved a string with columns specifications, how do I turn it into a cols() object?
– Leo Barlach
Nov 19 '18 at 18:13
I added more details to the question. Basically, if I have saved a string with columns specifications, how do I turn it into a cols() object?
– Leo Barlach
Nov 19 '18 at 18:13
add a comment |
1 Answer
1
active
oldest
votes
For you to obtain the second example, you can just use do.call:
aa <- c('c','n')
do.call(cols,as.list(aa))
cols(
= col_character(),
= col_number()
)
answered Nov 19 '18 at 18:43
OnyambuOnyambu
15.4k1519
add a comment |
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For you to obtain the second example, you can just use do.call:
aa <- c('c','n')
do.call(cols,as.list(aa))
cols(
= col_character(),
= col_number()
)
answered Nov 19 '18 at 18:43
OnyambuOnyambu
15.4k1519
add a comment |
For you to obtain the second example, you can just use do.call:
aa <- c('c','n')
do.call(cols,as.list(aa))
cols(
= col_character(),
= col_number()
)
answered Nov 19 '18 at 18:43
OnyambuOnyambu
15.4k1519
add a comment |
For you to obtain the second example, you can just use do.call:
aa <- c('c','n')
do.call(cols,as.list(aa))
cols(
= col_character(),
= col_number()
)
answered Nov 19 '18 at 18:43
OnyambuOnyambu
15.4k1519
For you to obtain the second example, you can just use do.call:
aa <- c('c','n')
do.call(cols,as.list(aa))
cols(
= col_character(),
= col_number()
)
answered Nov 19 '18 at 18:43
OnyambuOnyambu
15.4k1519
answered Nov 19 '18 at 18:43
OnyambuOnyambu
15.4k1519
answered Nov 19 '18 at 18:43
OnyambuOnyambu
15.4k1519
answered Nov 19 '18 at 18:43
OnyambuOnyambu
15.4k1519
15.4k1519
add a comment |
add a comment |
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Difficult to find an answer without seeing the exact error message, please edit your question to show what exactly happens ("doesn't work"). THX :-)
– R Yoda
Nov 16 '18 at 23:42
Check the documentation for
read_csv; you needcol_typesargument to be "One of NULL, a cols() specification, or a string." Currently you have none of these options.– Calum You
Nov 17 '18 at 0:18
I added more details to the question. Basically, if I have saved a string with columns specifications, how do I turn it into a cols() object?
– Leo Barlach
Nov 19 '18 at 18:13