Fully programmatically rename columns in R with dplyr - r

Question

I have sensor data, for several different sensor types, in many dataframes. I need to perform inner_joins on the dataframes so that I end up with one dataframe. The column names of the dataframes for a given sensor type are identical, e.g.
> z501h001
timeBgn soilTempMean soilTempVar
1 01:00:00 100 4
2 01:30:00 112 6
3 02:00:00 111 6
> z501h002
timeBgn soilTempMean soilTempVar
1 01:00:00 120 4
2 01:30:00 122 6
3 02:00:00 121 5
except there are way more columns. The column names are different for different types of sensors (they all have timeBgn in common) .
I need (in R) a flexible way to rename the columns (so I can tell which column corresponds to which sensor) based on adding a suffix to the existing column names for all columns except timeBgn (which is the common column by which the inner_join will be done).
Here is the Python / Pandas equivalent of what I am trying to do:
def rename_cols_by_sensor(df, sensor_name):
cols = df.columns
new_cols = [f'{c}_{sensor_name}' if c!='timeBgn' else c for c in cols]
df.columns = new_cols
I found most of a solution here:
programmatically rename columns in dplyr
The problem is that I cannot figure out how to make the cnames vector programmatically. I do not want to hard-code all of the myriad column names. As an example for z501h001 it would need to look like
cnames <- c('soilTempMean' = 'soilTempMean_z501h001', 'soilTempVar' = 'soilTempVar_z501h001')
the suffix (in the example: _z501h001) can be passed to the function so there is no need to discuss obtaining it here. The original names are easily obtained using names(df). All I need to know is how to put them together in this c("character" = "other_character") format.
I have tried:
rename_by_loc <- function(df, loc) {
old_names <- names(df)
new_names <- c()
loc = z501h001
for (name in old_names) {
if (name != "timeBgn") {
new_names <- c(new_names, paste(name, paste(name, loc, sep="_"), sep = " = ") )
}
}
return(new_names)
}
but that gives me names like "soilTempMean = soilTempMean_z501h001"
I need the = to be outside of the character strings. I have tried a few other things. None have been successful.
This problem is trivial using Pandas which makes me think I am missing something about column renaming in R.
Thanks.

Answer 1

We can use mget to get all the values of the objects with the pattern for object names starts with 'z' followed by 3 digits, 'h', and then 3 digits in a list, then use imap to loop over the list and rename all those columns except 'timeBgn' by concatenating (str_c) the original column with the object name
library(dplyr)
library(purrr)
library(stringr)
out <- mget(ls(pattern = "^z\\d{3}h\\d{3}$")) %>%
imap(~ {
nm1 <- .y
.x %>%
rename_with(~ str_c(., "_", nm1), -timeBgn)
})
The output will be a list. If we need to change the column name in the original object (not recommended), use list2env
list2env(out, .GlobalEnv)
Or using base R
v1 <- ls(pattern = "^z\\d{3}h\\d{3}$")
for(v in v1) {
tmp <- get(v)
i1 <- names(tmp) != 'timeBgn'
names(tmp)[i1] <- paste0(names(tmp)[i1], '_', v)
assign(v, tmp)
}