Reputation: 7958
change several column names() in data.frame() with str_replace_all()
I read this this question and practiced matching patterns, but I am still not figuring it.
I have a panel with the same measure, several times per year. Now, I want to rename them in a logical way. My raw data looks a bit like this,
set.seed(667)
dta <- data.frame(id = 1:6,
R1213 = runif(6),
R1224 = runif(6, 1, 2),
R1255 = runif(6, 2, 3),
R1235 = runif(6, 3, 4))
# install.packages(c("tidyverse"), dependencies = TRUE)
require(tidyverse)
(tbl <- dta %>% as_tibble())
#> # A tibble: 6 x 5
#> id R1213 R1224 R1255 R1235
#> <int> <dbl> <dbl> <dbl> <dbl>
#> 1 1 0.488 1.60 2.07 3.07
#> 2 2 0.692 1.42 2.76 3.19
#> 3 3 0.262 1.34 2.33 3.82
#> 4 4 0.330 1.77 2.61 3.93
#> 5 5 0.582 1.92 2.15 3.86
#> 6 6 0.930 1.88 2.56 3.59
Now, I use str_replace_all() to rename them, here with only one variable in where I use pate, and everything is fine (it might also be possible to optimize this in other ways, if so please feel to let me know),
names(tbl) <- tbl %>% names() %>%
str_replace_all('^R1.[125].$', 'A') %>%
str_replace_all('^R1.[3].$', paste0('A.2018.', 1))
tbl
#> # A tibble: 6 x 5
#> id A A A A.2018.1
#> <int> <dbl> <dbl> <dbl> <dbl>
#> 1 1 0.488 1.60 2.07 3.07
#> 2 2 0.692 1.42 2.76 3.19
#> 3 3 0.262 1.34 2.33 3.82
#> 4 4 0.330 1.77 2.61 3.93
#> 5 5 0.582 1.92 2.15 3.86
#> 6 6 0.930 1.88 2.56 3.59
Eveything call A is actually from the same year, let's say 2017, but with the suffix .1, .2, etc. need to appended. I start over and again use paste0('A.2017.', 1:3), but this time with three suffices,
tbl <- dta %>% as_tibble()
names(tbl) <- tbl %>% names() %>%
str_replace_all('^R1.[125].$', paste0('A.2017.', 1:3)) %>%
str_replace_all('^R1.[7].$', paste0('A.2018.', 1))
tbl
#> Warning message:
#> In stri_replace_all_regex(string, pattern, fix_replacement(replacement), :
#> longer object length is not a multiple of shorter object length
#> > tbl
#> # A tibble: 6 x 5
#> id A.2017.2 A.2017.3 A.2017.1 R1235
#> <int> <dbl> <dbl> <dbl> <dbl>
#> 1 1 0.488 1.60 2.07 3.07
#> 2 2 0.692 1.42 2.76 3.19
#> 3 3 0.262 1.34 2.33 3.82
#> 4 4 0.330 1.77 2.61 3.93
#> 5 5 0.582 1.92 2.15 3.86
#> 6 6 0.930 1.88 2.56 3.59
this does come out, but the order is reversed and I am told longer object length is not a multiple of shorter object length, but isen't 3 the right length? I am looking to do this in a cleaner and simpler way. Also, I don't really like names(tbl) <-, if that can be done in a more elegant way.
Upvotes: 1
Views: 1207
Answers (1)
Reputation: 466
Building on David's suggestion - how about something like the following using dplyr::rename_at?
library(dplyr)
## Get data
set.seed(667)
dta <- data.frame(id = 1:6,
R1213 = runif(6),
R1224 = runif(6, 1, 2),
R1255 = runif(6, 2, 3),
R1235 = runif(6, 3, 4)) %>%
as_tibble()
## Rename
dta <- dta %>%
rename_at(.vars = grep('^R1.[125].$', names(.)),
.funs = ~paste0("A.2017.", 1:length(.)))
dta
#> # A tibble: 6 x 5
#> id A.2017.1 A.2017.2 A.2017.3 R1235
#> <int> <dbl> <dbl> <dbl> <dbl>
#> 1 1 0.196 1.74 2.51 3.49
#> 2 2 0.478 1.85 2.06 3.69
#> 3 3 0.780 1.32 2.21 3.26
#> 4 4 0.705 1.49 2.49 3.33
#> 5 5 0.942 1.59 2.66 3.58
#> 6 6 0.906 1.90 2.87 3.93
Vectorised solution for multiple patterns
For a complete solution that can be used for multiple patterns and replacements, we can make use of purr::map2_dfc as follows.
library(dplyr)
library(purrr)
## Get data
set.seed(667)
dta <- data.frame(id = 1:6,
R1213 = runif(6),
R1224 = runif(6, 1, 2),
R1255 = runif(6, 2, 3),
R1235 = runif(6, 3, 4)) %>%
as_tibble()
## Define a function to keep a hold out data set, then rename iteratively for each pattern and replacement.
rename_multiple_years <- function(df, patterns,
replacements,
hold_out_var = "id") {
hold_out_df <- df %>%
select_at(.vars = hold_out_var)
rename_df <- map2_dfc(patterns, replacements, function(pattern, replacement) {
df %>%
rename_at(.vars = grep(pattern, names(.)),
.funs = ~paste0(replacement, 1:length(.))) %>%
select_at(.vars = grep(replacement, names(.)))
})
final_df <- bind_cols(hold_out_df, rename_df)
return(final_df)
}
## Call function on specified patterns and replacements
renamed_dta <- dta %>%
rename_multiple_years(patterns = c("^R1.[125].$", "^R1.[3].$"),
replacements = c("A.2017.", "A.2018."))
renamed_dta
#> # A tibble: 6 x 5
#> id A.2017.1 A.2017.2 A.2017.3 A.2018.1
#> <int> <dbl> <dbl> <dbl> <dbl>
#> 1 1 0.196 1.74 2.51 3.49
#> 2 2 0.478 1.85 2.06 3.69
#> 3 3 0.780 1.32 2.21 3.26
#> 4 4 0.705 1.49 2.49 3.33
#> 5 5 0.942 1.59 2.66 3.58
#> 6 6 0.906 1.90 2.87 3.93
Towards tidy data
Now that the variables have been renamed you might find it useful to have your data in a tidy format. The following using tidyr::gather might be useful.
library(tidyr)
library(dplyr)
#Use tidy dataframe gather all variables, split by "." and drop A column (or keep if a measurement id)
renamed_dta %>%
gather(key = "measure", value = "value", -id) %>%
separate(measure, c("A", "year", "measure"), "[[.]]") %>%
select(-A)
#> # A tibble: 24 x 4
#> id year measure value
#> <int> <chr> <chr> <dbl>
#> 1 1 2017 1 0.196
#> 2 2 2017 1 0.478
#> 3 3 2017 1 0.780
#> 4 4 2017 1 0.705
#> 5 5 2017 1 0.942
#> 6 6 2017 1 0.906
#> 7 1 2017 2 1.74
#> 8 2 2017 2 1.85
#> 9 3 2017 2 1.32
#> 10 4 2017 2 1.49
#> # ... with 14 more rows
Upvotes: 2
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