Reuse value of previous row during dplyr::mutate - r

I am trying to group events based on their time of occurrence. To achieve this, I simply calculate a diff over the timestamps and want to essentially start a new group if the diff is larger than a certain value. I would have tried like the code below. However, this is not working since the dialog variable is not available during the mutate it is created by.
library(tidyverse)
df <- data.frame(time = c(1,2,3,4,5,510,511,512,513), id = c(1,2,3,4,5,6,7,8,9))
> df
time id
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5
6 510 6
7 511 7
8 512 8
9 513 9
df <- df %>%
mutate(t_diff = c(NA, diff(time))) %>%
# This generates an error as dialog is not available as a variable at this point
mutate(dialog = ifelse(is.na(t_diff), id, ifelse(t_diff >= 500, id, lag(dialog, 1))))
# This is the desired result
> df
time id t_diff dialog
1 1 1 NA 1
2 2 2 1 1
3 3 3 1 1
4 4 4 1 1
5 5 5 1 1
6 510 6 505 6
7 511 7 1 6
8 512 8 1 6
9 513 9 1 6
In words, I want to add a column that points to the first element of each group. Thereby, the groups are distinguished at points at which the diff to the previous element is larger than 500.
Unfortunately, I have not found a clever workaround to achieve this in an efficient way using dplyr. Obviously, iterating over the data.frame with a loop would work, but would be very inefficient.
Is there a way to achieve this in dplyr?

Related

gather() per grouped variables in R for specific columns

I have a long data frame with players' decisions who worked in groups.
I need to convert the data in such a way that each row (individual observation) would contain all group members decisions (so we basically can see whether they are interdependent).
Let's say the generating code is:
group_id <- c(rep(1, 3), rep(2, 3))
player_id <- c(rep(seq(1, 3), 2))
player_decision <- seq(10,60,10)
player_contribution <- seq(6,1,-1)
df <-
data.frame(group_id, player_id, player_decision, player_contribution)
So the initial data looks like:
group_id player_id player_decision player_contribution
1 1 1 10 6
2 1 2 20 5
3 1 3 30 4
4 2 1 40 3
5 2 2 50 2
6 2 3 60 1
But I need to convert it to wide per each group, but only for some of these variables, (in this example specifically for player_contribution, but in such a way that the rest of the data remains. So the head of the converted data would be:
data.frame(group_id=c(1,1),
player_id=c(1,2),
player_decision=c(10,20),
player_1_contribution=c(6,6),
player_2_contribution=c(5,5),
player_3_contribution=c(4,6)
)
group_id player_id player_decision player_1_contribution player_2_contribution player_3_contribution
1 1 1 10 6 5 4
2 1 2 20 6 5 6
I suspect I need to group_by in dplyr and then somehow gather per group but only for player_contribution (or a vector of variables). But I really have no clue how to approach it. Any hints would be welcome!
Here is solution using tidyr and dplyr.
Make a dataframe with the columns for the players contributions. Then join this dataframe back onto the columns of interest from the original Dataframe.
library(tidyr)
library(dplyr)
wide<-pivot_wider(df, id_cols= - player_decision,
names_from = player_id,
values_from = player_contribution,
names_prefix = "player_contribution_")
answer<-left_join(df[, c("group_id", "player_id", "player_decision") ], wide)
answer
group_id player_id player_decision player_contribution_1 player_contribution_2 player_contribution_3
1 1 1 10 6 5 4
2 1 2 20 6 5 4
3 1 3 30 6 5 4
4 2 1 40 3 2 1
5 2 2 50 3 2 1
6 2 3 60 3 2 1

Panel Data in R: Get complete cases of data based on individuals

I'm working on an unbalanced panel dataset. Data came from a game and for every user (user_id) in the record I have data for every level (level) of the game. As recording data started some time after introduction of the game, for some users I don't have data regarding the first levels, that's why I want to throw them out in a first step.
I've tried the complete.cases-function, but it only excludes the rows with the missing values (NAs), but not data for the whole user with missing values in level 1.
panel <- panel[complete.cases(panel), ]
That's why I need a code that excludes every user who has no record in level 1 (which in my dataset means he has an "NA" at one of the dependent variables, i.e. number of activities).
Update #1:
Data looks like this (thanks to thc):
> game_data <- data.frame(player = c(1,1,1,2,2,2,3,3,3), level = c(1,2,3,1,2,3,1,2,3), score=c(0,150,170,80,100,110,75,100,0))
> game_data
player level score
1 1 1 0
2 1 2 150
3 1 3 170
4 2 1 80
5 2 2 100
6 2 3 110
7 3 1 75
8 3 2 100
9 3 3 0
I now want to exclude data from player 1, because he has a score of 0 in level 1.
Here is one approach
Example data:
game_data <- data.frame(player = c(1,1,2,2,2,3,3,3), level = c(2,3,1,2,3,1,2,3), score=sample(100, 8))
> game_data
player level score
1 1 2 19
2 1 3 13
3 2 1 65
4 2 2 32
5 2 3 22
6 3 1 98
7 3 2 58
8 3 3 84
library(dplyr)
game_data %>% group_by(player) %>% filter(any(level == 1)) %>% as.data.frame
player level score
1 2 1 65
2 2 2 32
3 2 3 22
4 3 1 98
5 3 2 58
6 3 3 84
I think I now find a solution with your help:
game_data %>% group_by(player) %>% filter(any(level == 1 & score > 0)) %>% as.data.frame
This seems to work and I just needed a little adjustment from your code thc, thank you very much for your help!

Divide each rows by a different number

I've looked on the internet but I haven found the answer that I'm looking for, but shure it's out there...
I've a data frame, and I want to divide (or any other operation) every cell of a row by a value that it's placed in the second column of my data frame.
So first row from col3 to last col, divide each cell by the value of col2 of that certain row, and so on for every single row.
I have solved this by using a For loop, col2 (delta) it's now a vector, and col3 to end it's a data.frame (mu). The results are append to a new data frame by using rbind.
The question is; I'm pretty sure that this can be done by using the function apply, sapply or similar, but I have not gotten the results that I've been looking so far (not the good ones as I do with the loop for). ¿How can I do it without using a loop for?
Loop for I've been using so far.
In resume.
I want to divide each mu by the delta value of it's own row.
for (i in 1:(dim(mu)[1])){
RA_row <- mu[i,]/delta[i]
RA <- rbind(RA, RA_row)
}
transcript delta mu_5 mu_15 mu_25 mu_35 mu_45 mu_55 mu_65
1 YAL001C 0.066702720 2.201787e-01 1.175731e-01 2.372506e-01 0.139281317 0.081723456 1.835414e-01 1.678318e-01
2 YAL002W 0.106000180 3.685822e-01 1.326865e-01 2.887973e-01 0.158207858 0.193476082 1.867039e-01 1.776946e-01
3 YAL003W 0.022119345 2.271518e+00 2.390637e+00 1.651997e+00 3.802739732 2.733559839 2.772454e+00 3.571712e+00
Thanks
It appears as though you want just:
mu2 <- mu[-(1:2)]/mu[[2]]
# same as mu[-(1:2), ]/mu[['delta']]
That should produce a new dataframe with the division by row. Somewhat more dangerous would be to do the division "in place".
mu[-(1:2)] <- mu[-(1:2)]/mu[[2]]
> mu <- data.frame(a=1,b=1:10, c=rnorm(10), d=rnorm(10) )
> mu
a b c d
1 1 1 -1.91435943 0.45018710
2 1 2 1.17658331 -0.01855983
3 1 3 -1.66497244 -0.31806837
4 1 4 -0.46353040 -0.92936215
5 1 5 -1.11592011 -1.48746031
6 1 6 -0.75081900 -1.07519230
7 1 7 2.08716655 1.00002880
8 1 8 0.01739562 -0.62126669
9 1 9 -1.28630053 -1.38442685
10 1 10 -1.64060553 1.86929062
> (mu2 <- mu[-(1:2)]/mu[[2]])
c d
1 -1.914359426 0.450187101
2 0.588291656 -0.009279916
3 -0.554990812 -0.106022792
4 -0.115882600 -0.232340537
5 -0.223184021 -0.297492062
6 -0.125136500 -0.179198716
7 0.298166649 0.142861258
8 0.002174452 -0.077658337
9 -0.142922281 -0.153825205
10 -0.164060553 0.186929062
> (mu[-(1:2)] <- mu[-(1:2)]/mu[[2]] )
> mu
a b c d
1 1 1 -1.914359426 0.450187101
2 1 2 0.588291656 -0.009279916
3 1 3 -0.554990812 -0.106022792
4 1 4 -0.115882600 -0.232340537
5 1 5 -0.223184021 -0.297492062
6 1 6 -0.125136500 -0.179198716
7 1 7 0.298166649 0.142861258
8 1 8 0.002174452 -0.077658337
9 1 9 -0.142922281 -0.153825205
10 1 10 -0.164060553 0.186929062

Select max or equal value from several columns in a data frame

I'm trying to select the column with the highest value for each row in a data.frame. So for instance, the data is set up as such.
> df <- data.frame(one = c(0:6), two = c(6:0))
> df
one two
1 0 6
2 1 5
3 2 4
4 3 3
5 4 2
6 5 1
7 6 0
Then I'd like to set another column based on those rows. The data frame would look like this.
> df
one two rank
1 0 6 2
2 1 5 2
3 2 4 2
4 3 3 3
5 4 2 1
6 5 1 1
7 6 0 1
I imagine there is some sort of way that I can use plyr or sapply here but it's eluding me at the moment.
There might be a more efficient solution, but
ranks <- apply(df, 1, which.max)
ranks[which(df[, 1] == df[, 2])] <- 3
edit: properly spaced!

Calculating the occurrences of numbers in the subsets of a data.frame

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))

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