如何修剪数据帧列表中的所有空间R

Question

the data that I am ingesting in my R script are full of white spaces (the bane of my existance). Thus far I have been using trimws within my functions so that my joins return true results. I am wondering if it is possible trim the white space in all columns and all data frames that I have stored in a list.

ParsedFile <- grep("ItemDetail", names(.GlobalEnv), value = TRUE)

this creates a list of the data frames that I want to remove the white space of in all the fields.I thought this would work but lapply does not seem to want to write the information back to the data frame.

as.data.frame(lapply(get(ParsedFile), trimws))

Moreover, I see it only print 1 result to the console where I expect a result for each data frame.

Can someone please help me out?

Thanks

Answer 1

Use purrr and its map function to iterate over the list of data frames, then map_df to iterate over the columns in each data frame, which will return the results as data_frames .

library(purrr)
ParsedFile %>% map(~map_df(., ~trimws(.)))

Answer 2

IIUC, here's a way to do it. I don't know what your desired output is. But, this method returns a list of dataframe. This might give you some thoughts:

# here df1, df2 are data frames
df1 = data.frame(name = c(' mani ','san ',' fdfg '))
df2 = data.frame(name = c(' mani ','gh ',' fdfg '))

# do this
lapply(c(df1, df2), function(x) do.call(rbind, lapply(x, trimws)))

$name
     [,1]  
[1,] "mani"
[2,] "san" 
[3,] "fdfg"

$name
     [,1]  
[1,] "mani"
[2,] "gh"  
[3,] "fdfg"

Second Method: For your case :-

# save intermediate list
temp <- lapply(get(ParsedFile), function(x) do.call(rbind, lapply(x, trimws)))

# convert list to df
new_df <- data.frame(new_col = do.call(rbind, temp))

print(new_df)

    new_col
1    mani
2     san
3    fdfg
4    mani
5      gh
6    fdfg