在R中处理多个数据帧

Question

I have over 40 data frame in R with the same exact variables. I have manipulated one of them and I would like to do those manipulations to all of them. So far I've created a list of the data frames

dataframes <- ls(pattern = "file_")

(All of the data frames started with file_)

But when I run

lapply(dataframes,function(x){
x$bin <- cut(x$Distance, breaks  = c(0, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 750, 1000, 1250, 
                                              1500, 2000, 2500, 6000), labels = NULL, include.lowest = T)
return(x)  
})

It returns

Error in x$Distance : $ operator is invalid for atomic vectors

Here is a look at one of the data frames. This is the data contained in one of the data frames.

Coast   STCG.2.Commodity    Port.of.Entry       Domestic.Destinations Distance
    1 East/Gulf Alcoholicbeverages Baltimore MD MSA               Albany NY CSA    285.8
    2 East/Gulf Alcoholicbeverages Baltimore MD MSA Atlanta GA-AL CSA (GA Part)    586.0
    3 East/Gulf Alcoholicbeverages Baltimore MD MSA               Austin TX MSA   1344.5
    4 East/Gulf Alcoholicbeverages Baltimore MD MSA               Austin TX MSA   1344.5
    5 East/Gulf Alcoholicbeverages Baltimore MD MSA               Austin TX MSA   1344.5
    6 East/Gulf Alcoholicbeverages Baltimore MD MSA            Baltimore MD MSA      0.0
                                                                        Index         Domestic.Mode Total.Ktons   Ton_Share Total.Ton.Mile Total.M.
    1               East/GulfAlcoholic beveragesBaltimore MD MSAAlbany NY CSA                 Truck      0.0005           1     0.00019568   0.0022
    2 East/GulfAlcoholic beveragesBaltimore MD MSAAtlanta GA-AL CSA (GA Part)                 Truck      0.2639           1     0.17538398   0.1922
    3               East/GulfAlcoholic beveragesBaltimore MD MSAAustin TX MSA                 Truck      1.0548 0.419804187     1.64523022   0.5473
    4               East/GulfAlcoholic beveragesBaltimore MD MSAAustin TX MSA                  Rail      0.9675 0.385059301     1.69025058   0.5020
    5               East/GulfAlcoholic beveragesBaltimore MD MSAAustin TX MSA Multiple modes & mail      0.4903 0.195136512     0.88638634   0.2544
    6            East/GulfAlcoholic beveragesBaltimore MD MSABaltimore MD MSA                 Truck     52.7997 0.999873121     1.24978071 205.7857
      Total.Current.M.                bin
    1           0.0025          (250,300]
    2           0.2128          (500,750]
    3           0.6061 (1.25e+03,1.5e+03]
    4           0.5560 (1.25e+03,1.5e+03]
    5           0.2818 (1.25e+03,1.5e+03]
    6         227.9075             [0,50]

Answer 1

To access a data frame by its name use get() as in get("file_x") . With multiple data frames use mget() . In your case I think you want:

dataframes <- mget(ls(pattern = "file_"))

lapply(dataframes,function(x){
x$bin <- cut(x$Distance, breaks  = c(0, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 750, 1000, 1250, 
                                          1500, 2000, 2500, 6000), labels = NULL, include.lowest = T)
return(x)  
})