I'm kinda new to R and still looking for ways to make my code more elegant. I want to create multiple datasets in a more efficient way, each based on a particular value over different columns.
This is my dataset:
df<-data.frame(A=c(1,2,2,3,4,5,1,1,2,3),
B=c(4,4,2,3,4,2,1,5,2,2),
C=c(3,3,3,3,4,2,5,1,2,3),
D=c(1,2,5,5,5,4,5,5,2,3),
E=c(1,4,2,3,4,2,5,1,2,3),
dummy1=c("yes","yes","no","no","no","no","yes","no","yes","yes"),
dummy2=c("high","low","low","low","high","high","high","low","low","high"))
And I need each column to be a factor:
df[colnames(df)] <- lapply(df[colnames(df)], factor)
Now, what I want to obtain is one dataframe called "Likert_rank_yes" that contains all the observations that in the column "dummy1" have "yes", one dataframe called "Likert_rank_no" that contains all the observations that in the column "dummy1" have "no", one dataframe called "Likert_rank_high" that contains all the observations that in the column "dummy2" have "high" and so on for all my other dummies.
I want to loop or streamline the process in some way, so that there are few commands to run to get all the datasets I need.
The first two dataframes should look something like this:
Dataframe called "Likert_rank_yes" that contains all the observations that in the column "dummy1" have "yes"
Dataframe called "Likert_rank_no" that contains all the observations that in the column "dummy1" have "no"
I have to do this with several dummies with multiple levels and would like to automate/loop the process or make it more efficient, so that I don't have to subset and rename every dataframe for each dummy level. Ideally I would also need to drop the last column in each df created (the one containing the dummy considered).
I tried splitting like below but it seems it is not possible using multiple values, I just get 4 dfs (yes AND high observations, yes AND low obs, no AND high obs etc.) like so:
Splitting with a list of columns doesn't work
list_df <- split(df[c(1:5)], list(df$dummy1,df$dummy2), sep=".")
Can you help? Thanks in advance!
You need two lapplys:
vals <- colnames(df)[1:5]
dummies <- colnames(df)[-(1:5)]
step1 <- lapply(dummies, function(x) df[, c(vals, x)])
step2 <- lapply(step1, function(x) split(x, x[, 6]))
names(step2) <- dummies
step2
# $dummy1
# $dummy1$no
# A B C D E dummy1
# 3 2 2 3 5 2 no
# 4 3 3 3 5 3 no
# 5 4 4 4 5 4 no
# 6 5 2 2 4 2 no
# 8 1 5 1 5 1 no
#
# $dummy1$yes
# A B C D E dummy1
# 1 1 4 3 1 1 yes
# 2 2 4 3 2 4 yes
# 7 1 1 5 5 5 yes
# 9 2 2 2 2 2 yes
# 10 3 2 3 3 3 yes
#
#
# $dummy2
# $dummy2$high
# A B C D E dummy2
# 1 1 4 3 1 1 high
# 5 4 4 4 5 4 high
# 6 5 2 2 4 2 high
# 7 1 1 5 5 5 high
# 10 3 2 3 3 3 high
#
# $dummy2$low
# A B C D E dummy2
# 2 2 4 3 2 4 low
# 3 2 2 3 5 2 low
# 4 3 3 3 5 3 low
# 8 1 5 1 5 1 low
# 9 2 2 2 2 2 low
For the first data set ("dummy1" and "no") use step2$dummy1$no or step2[[1]][[1]] or step2[["dummy1"]][["no"]].
For programming purposes it is usually better to keep the list intact since it makes it simple to write code that processes all of the data frames in the list without having to specify them individually.
You are very close:
tbls <- unlist(step2, recursive=FALSE)
list2env(tbls, envir=.GlobalEnv)
ls()
# [1] "df" "dummies" "dummy1.no" "dummy1.yes" "dummy2.high" "dummy2.low" "step1" "step2" "tbls" "vals"
This will create the same set of tables.
There is a wide data set, a simple example is
df<-data.frame("id"=c(1:6),
"ax"=c(1,2,2,3,4,4),
"bx"=c(7,8,8,9,10,10),
"cx"=c(11,12,12,13,14,14))
I'm looking for a way to assign the values in "ax" to column "bx" and "cx". Here, imagine we have thousands of columns we intend to replace with "ax", so I want this to be done in an automated approach using R. The expected output look like
df<-data.frame("id"=c(1:6),
"ax"=c(1,2,2,3,4,4),
"bx"=c(1,2,2,3,4,4),
"cx"=c(1,2,2,3,4,4))
I've thought of, and tried using mutate_at and ends_with, but this has not work for me. For example, I tried
df %>%
mutate_at(vars(ends_with("x")), labels = "ax")
and this prints an error. Not sure what's wrong or what's to be added to get this working, so I would like to request your help on this. Thank you very much!
A simple way using base R would be :
change_cols <- grep('x$', names(df))
df[change_cols] <- df$ax
df
# id ax bx cx
#1 1 1 1 1
#2 2 2 2 2
#3 3 2 2 2
#4 4 3 3 3
#5 5 4 4 4
#6 6 4 4 4
I would suggest this tidyverse approach using across() to select the range of variables you want:
library(tidyverse)
#Data
df<-data.frame("id"=c(1:6),
"ax"=c(1,2,2,3,4,4),
"bx"=c(7,8,8,9,10,10),
"cx"=c(11,12,12,13,14,14))
#Mutate
df %>% mutate(across(c(bx:cx), ~ ax))
Output:
id ax bx cx
1 1 1 1 1
2 2 2 2 2
3 3 2 2 2
4 4 3 3 3
5 5 4 4 4
6 6 4 4 4
Another option with mutate_at()
df %>%
mutate_at(vars(matches("x$")), ~ax)
# id ax bx cx
# 1 1 1 1 1
# 2 2 2 2 2
# 3 3 2 2 2
# 4 4 3 3 3
# 5 5 4 4 4
# 6 6 4 4 4
I have a table like this
table(mtcars$gear, mtcars$cyl)
I want to rank the rows by the ones with more observations in the 4 cylinder. E.g.
4 6 8
4 8 4 0
5 2 1 2
3 1 2 12
I have been playing with order/sort/rank without much success. How could I order tables output?
We can convert table to data.frame and then order by the column.
sort_col <- "4"
tab <- as.data.frame.matrix(table(mtcars$gear, mtcars$cyl))
tab[order(-tab[sort_col]), ]
# OR tab[order(tab[sort_col], decreasing = TRUE), ]
# 4 6 8
#4 8 4 0
#5 2 1 2
#3 1 2 12
If we don't want to convert it into data frame and want to maintain the table structure we can do
tab <- table(mtcars$gear, mtcars$cyl)
tab[order(-tab[,dimnames(tab)[[2]] == sort_col]),]
# 4 6 8
# 4 8 4 0
# 5 2 1 2
# 3 1 2 12
Could try this. Use sort for the relevant column, specifying decreasing=TRUE; take the names of the sorted rows and subset using those.
table(mtcars$gear, mtcars$cyl)[names(sort(table(mtcars$gear, mtcars$cyl)[,1], dec=T)), ]
4 6 8
4 8 4 0
5 2 1 2
3 1 2 12
In the same scope as Milan, but using the order() function, instead of looking for names() in a sort()-ed list.
The [,1] is to look at the first column when ordering.
table(mtcars$gear, mtcars$cyl)[order(table(mtcars$gear, mtcars$cyl)[,1], decreasing=T),]
I have a data frame in R which is similar to the follows. Actually my real ’df’ dataframe is much bigger than this one here but I really do not want to confuse anybody so that is why I try to simplify things as much as possible.
So here’s the data frame.
id <-c(1,1,1,1,1,1,1,1,1,1,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3)
a <-c(3,1,3,3,1,3,3,3,3,1,3,2,1,2,1,3,3,2,1,1,1,3,1,3,3,3,2,1,1,3)
b <-c(3,2,1,1,1,1,1,1,1,1,1,2,1,3,2,1,1,1,2,1,3,1,2,2,1,3,3,2,3,2)
c <-c(1,3,2,3,2,1,2,3,3,2,2,3,1,2,3,3,3,1,1,2,3,3,1,2,2,3,2,2,3,2)
d <-c(3,3,3,1,3,2,2,1,2,3,2,2,2,1,3,1,2,2,3,2,3,2,3,2,1,1,1,1,1,2)
e <-c(2,3,1,2,1,2,3,3,1,1,2,1,1,3,3,2,1,1,3,3,2,2,3,3,3,2,3,2,1,3)
df <-data.frame(id,a,b,c,d,e)
df
Basically what I would like to do is to get the occurrences of numbers for each column (a,b,c,d,e) and for each id group (1,2,3) (for this latter grouping see my column ’id’).
So, for column ’a’ and for id number ’1’ (for the latter see column ’id’) the code would be something like this:
as.numeric(table(df[1:10,2]))
##The results are:
[1] 3 7
Just to briefly explain my results: in column ’a’ (and regarding only those records which have number ’1’ in column ’id’) we can say that number '1' occured 3 times and number '3' occured 7 times.
Again, just to show you another example. For column ’a’ and for id number ’2’ (for the latter grouping see again column ’id’):
as.numeric(table(df[11:20,2]))
##After running the codes the results are:
[1] 4 3 3
Let me explain a little again: in column ’a’ and regarding only those observations which have number ’2’ in column ’id’) we can say that number '1' occured 4 times, number '2' occured 3 times and number '3' occured 3 times.
So this is what I would like to do. Calculating the occurrences of numbers for each custom-defined subsets (and then collecting these values into a data frame). I know it is not a difficult task but the PROBLEM is that I’m gonna have to change the input ’df’ dataframe on a regular basis and hence both the overall number of rows and columns might change over time…
What I have done so far is that I have separated the ’df’ dataframe by columns, like this:
for (z in (2:ncol(df))) assign(paste("df",z,sep="."),df[,z])
So df.2 will refer to df$a, df.3 will equal df$b, df.4 will equal df$c etc. But I’m really stuck now and I don’t know how to move forward…
Is there a proper, ”automatic” way to solve this problem?
How about -
> library(reshape)
> dftab <- table(melt(df,'id'))
> dftab
, , value = 1
variable
id a b c d e
1 3 8 2 2 4
2 4 6 3 2 4
3 4 2 1 5 1
, , value = 2
variable
id a b c d e
1 0 1 4 3 3
2 3 3 3 6 2
3 1 4 5 3 4
, , value = 3
variable
id a b c d e
1 7 1 4 5 3
2 3 1 4 2 4
3 5 4 4 2 5
So to get the number of '3's in column 'a' and group '1'
you could just do
> dftab[3,'a',1]
[1] 4
A combination of tapply and apply can create the data you want:
tapply(df$id,df$id,function(x) apply(df[id==x,-1],2,table))
However, when a grouping doesn't have all the elements in it, as in 1a, the result will be a list for that id group rather than a nice table (matrix).
$`1`
$`1`$a
1 3
3 7
$`1`$b
1 2 3
8 1 1
$`1`$c
1 2 3
2 4 4
$`1`$d
1 2 3
2 3 5
$`1`$e
1 2 3
4 3 3
$`2`
a b c d e
1 4 6 3 2 4
2 3 3 3 6 2
3 3 1 4 2 4
$`3`
a b c d e
1 4 2 1 5 1
2 1 4 5 3 4
3 5 4 4 2 5
I'm sure someone will have a more elegant solution than this, but you can cobble it together with a simple function and dlply from the plyr package.
ColTables <- function(df) {
counts <- list()
for(a in names(df)[names(df) != "id"]) {
counts[[a]] <- table(df[a])
}
return(counts)
}
results <- dlply(df, "id", ColTables)
This gets you back a list - the first "layer" of the list will be the id variable; the second the table results for each column for that id variable. For example:
> results[['2']]['a']
$a
1 2 3
4 3 3
For id variable = 2, column = a, per your above example.
A way to do it is using the aggregate function, but you have to add a column to your dataframe
> df$freq <- 0
> aggregate(freq~a+id,df,length)
a id freq
1 1 1 3
2 3 1 7
3 1 2 4
4 2 2 3
5 3 2 3
6 1 3 4
7 2 3 1
8 3 3 5
Of course you can write a function to do it, so it's easier to do it frequently, and you don't have to add a column to your actual data frame
> frequency <- function(df,groups) {
+ relevant <- df[,groups]
+ relevant$freq <- 0
+ aggregate(freq~.,relevant,length)
+ }
> frequency(df,c("b","id"))
b id freq
1 1 1 8
2 2 1 1
3 3 1 1
4 1 2 6
5 2 2 3
6 3 2 1
7 1 3 2
8 2 3 4
9 3 3 4
You didn't say how you'd like the data. The by function might give you the output you like.
by(df, df$id, function(x) lapply(x[,-1], table))