I have a time-series dataset in which I would like to refer to a value in a previous year, if it exists. I therefore create a helper column with the date I am referring to and expect the code to retrieve the value from that exact year. However, this is not happening, rather it retrieves the same value in all rows, corresponding to the first possible year.
I use the following code
library(dplyr)
library(lubridate)
dataset <- data.frame(names=c("a","a","a","a","a","a"),
values=c(2,3,4,5,6,7),
dates=dmy(c("01/01/2010","01/01/2011","01/01/2012","01/01/2013","01/01/2014","01/01/2015")))
dataset_calc <- dataset %>%
group_by(names) %>%
mutate(yoy=case_when(dates>=dmy("01/01/2011") ~ dates-years(1),
TRUE ~ dmy("01/01/2010"))) %>%
ungroup()
final <- dataset_calc %>%
mutate(yoyval= values[dates==yoy])
But get this result:
names values dates yoy yoyval
<chr> <dbl> <date> <date> <dbl>
1 a 2 2010-01-01 2010-01-01 2
2 a 3 2011-01-01 2010-01-01 2
3 a 4 2012-01-01 2011-01-01 2
4 a 5 2013-01-01 2012-01-01 2
5 a 6 2014-01-01 2013-01-01 2
6 a 7 2015-01-01 2014-01-01 2
Where I'd expect to get the following:
names values dates yoy yoyval
<chr> <dbl> <date> <date> <dbl>
1 a 2 2010-01-01 2010-01-01 2
2 a 3 2011-01-01 2010-01-01 2
3 a 4 2012-01-01 2011-01-01 3
4 a 5 2013-01-01 2012-01-01 4
5 a 6 2014-01-01 2013-01-01 5
6 a 7 2015-01-01 2014-01-01 6
Am I not using the conditioning in the square brackets correctly, or do I misunderstand how mutate uses the condition?
You can do a left_join on the new column yoy with the original dates to find the corresponding values for each year:
final <- dataset_calc %>%
left_join(dataset_calc %>% select(values, dates), by = c('yoy' = 'dates'))
This gives the desired result.
If you want to incorporate the action in the existing pipeline, you can reference the intermediate result with eval(.) and perform a sort-of self join:
dataset_calc <- dataset %>%
group_by(names) %>%
mutate(yoy=case_when(dates>=dmy("01/01/2011") ~ dates-years(1),
TRUE ~ dmy("01/01/2010"))) %>%
ungroup() %>%
left_join(eval(.) %>% select(values, dates), by = c('yoy' = 'dates'))
If I had:
person_ID visit date
1 2/25/2001
1 2/27/2001
1 4/2/2001
2 3/18/2004
3 9/22/2004
3 10/27/2004
3 5/15/2008
and I wanted another column to indicate the earliest recurring observation within 90 days, grouped by patient ID, with the desired output:
person_ID visit date date
1 2/25/2001 2/27/2001
1 2/27/2001 4/2/2001
1 4/2/2001 NA
2 3/18/2004 NA
3 9/22/2004 10/27/2004
3 10/27/2004 NA
3 5/15/2008 NA
Thank you!
We convert the 'visit_date' to Date class, grouped by 'person_ID', create a binary column that returns 1 if the difference between the current and next visit_date is less than 90 or else 0, using this column, get the correponding next visit_date' where the value is 1
library(dplyr)
library(lubridate)
library(tidyr)
df1 %>%
mutate(visit_date = mdy(visit_date)) %>%
group_by(person_ID) %>%
mutate(i1 = replace_na(+(difftime(lead(visit_date),
visit_date, units = 'day') < 90), 0),
date = case_when(as.logical(i1)~ lead(visit_date)), i1 = NULL ) %>%
ungroup
-output
# A tibble: 7 x 3
# person_ID visit_date date
# <int> <date> <date>
#1 1 2001-02-25 2001-02-27
#2 1 2001-02-27 2001-04-02
#3 1 2001-04-02 NA
#4 2 2004-03-18 NA
#5 3 2004-09-22 2004-10-27
#6 3 2004-10-27 NA
#7 3 2008-05-15 NA
I would like to calculate monthly non-cumulative subtotals for my data frame (df).
"date" "id" "change"
2010-01-01 1 NA
2010-01-07 2 3
2010-01-15 2 -1
2010-02-01 1 NA
2010-02-04 2 7
2010-02-22 2 -2
2010-02-26 2 4
2010-03-01 1 NA
2010-03-14 2 -4
2010-04-01 1 NA
A new period starts at the first day of a new month. The column "id" serves as a grouping variable for the beginning of a new period (==1) and observations within a period (==2). The goal is to sum up all changes within a month and then restart at 0 for the next period. The output should be stored in an additional column of df.
Here a reproducible example for my data frame:
require(dplyr)
require(tidyr)
require(lubridate)
date <- ymd(c("2010-01-01","2010-01-07","2010-01-15","2010-02-01","2010-02-04","2010-02-22","2010-02-26","2010-03-01","2010-03-14","2010-04-01"))
df <- data.frame(date)
df$id <- as.numeric((c(1,2,2,1,2,2,2,1,2,1)))
df$change <- c(NA,3,-1,NA,7,-2,4,NA,-4,NA)
What i have tried to do:
df <- df %>%
group_by(id) %>%
mutate(total = cumsum(change)) %>%
ungroup() %>%
fill(total, .direction = "down") %>%
filter(id == 1)
Which leads to this output:
"date" "id" "change" "total"
2010-01-01 1 NA NA
2010-02-01 1 NA 2
2010-03-01 1 NA 11
2010-04-01 1 NA 7
The problem lies with the function cumsum, which accumulates all the preceding values from a group and does not restart at 0 for a new period.
The desired output looks like this:
"date" "id" "change" "total"
2010-01-01 1 NA NA
2010-02-01 1 NA 2
2010-03-01 1 NA 9
2010-04-01 1 NA -4
The rows with "id" ==1 show the sum of changes for all preceding columns with "id" ==2, restarting at 0 for every period. Does there exist a specific command for this type of problem? Could anyone provide a corrected alternative to the code above?
We may need to also use year-month formatted 'date' in the grouping variable to reset for each month
library(dplyr)
df %>%
group_by(id, grp = format(date, "%Y-%m")) %>%
mutate(total = cumsum(change)) %>%
ungroup() %>%
fill(total, .direction = "down") %>%
filter(id == 1) %>%
ungroup %>%
select(-grp)
# A tibble: 4 x 4
# date id change total
# <date> <dbl> <dbl> <dbl>
#1 2010-01-01 1 NA NA
#2 2010-02-01 1 NA 2
#3 2010-03-01 1 NA 9
#4 2010-04-01 1 NA -4
I have a data in which I have 2 fields in a table sf -> Customer id and Buy_date. Buy_date is unique but for each customer, but there can be more than 3 different values of Buy_dates for each customer. I want to calculate difference in consecutive Buy_date for each Customer and its mean value. How can I do this.
Example
Customer Buy_date
1 2018/03/01
1 2018/03/19
1 2018/04/3
1 2018/05/10
2 2018/01/02
2 2018/02/10
2 2018/04/13
I want the results for each customer in the format
Customer mean
Here's a dplyr solution.
Your data:
df <- data.frame(Customer = c(1,1,1,1,2,2,2), Buy_date = c("2018/03/01", "2018/03/19", "2018/04/3", "2018/05/10", "2018/01/02", "2018/02/10", "2018/04/13"))
Grouping, mean Buy_date calculation and summarising:
library(dplyr)
df %>% group_by(Customer) %>% mutate(mean = mean(as.POSIXct(Buy_date))) %>% group_by(Customer, mean) %>% summarise()
Output:
# A tibble: 2 x 2
# Groups: Customer [?]
Customer mean
<dbl> <dttm>
1 1 2018-03-31 06:30:00
2 2 2018-02-17 15:40:00
Or as #r2evans points out in his comment for the consecutive days between Buy_dates:
df %>% group_by(Customer) %>% mutate(mean = mean(diff(as.POSIXct(Buy_date)))) %>% group_by(Customer, mean) %>% summarise()
Output:
# A tibble: 2 x 2
# Groups: Customer [?]
Customer mean
<dbl> <time>
1 1 23.3194444444444
2 2 50.4791666666667
I am not exactly sure of the desired output but this what I think you want.
library(dplyr)
library(zoo)
dat <- read.table(text =
"Customer Buy_date
1 2018/03/01
1 2018/03/19
1 2018/04/3
1 2018/05/10
2 2018/01/02
2 2018/02/10
2 2018/04/13", header = T, stringsAsFactors = F)
dat$Buy_date <- as.Date(dat$Buy_date)
dat %>% group_by(Customer) %>% mutate(diff_between = as.vector(diff(zoo(Buy_date), na.pad=TRUE)),
mean_days = mean(diff_between, na.rm = TRUE))
This produces:
Customer Buy_date diff_between mean_days
<int> <date> <dbl> <dbl>
1 1 2018-03-01 NA 23.3
2 1 2018-03-19 18 23.3
3 1 2018-04-03 15 23.3
4 1 2018-05-10 37 23.3
5 2 2018-01-02 NA 50.5
6 2 2018-02-10 39 50.5
7 2 2018-04-13 62 50.5
EDITED BASED ON USER COMMENTS:
Because you said that you have factors and not characters just convert them by doing the following:
dat$Buy_date <- as.Date(as.character(dat$Buy_date))
dat$Customer <- as.character(dat$Customer)
I have irregular timeseries data representing a certain type of transaction for users. Each line of data is timestamped and represents a transaction at that time. By the irregular nature of the data some users might have 100 rows in a day and other users might have 0 or 1 transaction in a day.
The data might look something like this:
data.frame(
id = c(1, 1, 1, 1, 1, 2, 2, 3, 4),
date = c("2015-01-01",
"2015-01-01",
"2015-01-05",
"2015-01-25",
"2015-02-15",
"2015-05-05",
"2015-01-01",
"2015-08-01",
"2015-01-01"),
n_widgets = c(1,2,3,4,4,5,2,4,5)
)
id date n_widgets
1 1 2015-01-01 1
2 1 2015-01-01 2
3 1 2015-01-05 3
4 1 2015-01-25 4
5 1 2015-02-15 4
6 2 2015-05-05 5
7 2 2015-01-01 2
8 3 2015-08-01 4
9 4 2015-01-01 5
Often I'd like to know some rolling statistics about users. For example: for this user on a certain day, how many transactions occurred in the previous 30 days, how many widgets were sold in the previous 30 days etc.
Corresponding to the above example, the data should look like:
id date n_widgets n_trans_30 total_widgets_30
1 1 2015-01-01 1 1 1
2 1 2015-01-01 2 2 3
3 1 2015-01-05 3 3 6
4 1 2015-01-25 4 4 10
5 1 2015-02-15 4 2 8
6 2 2015-05-05 5 1 5
7 2 2015-01-01 2 1 2
8 3 2015-08-01 4 1 4
9 4 2015-01-01 5 1 5
If the time window is daily then the solution is simple: data %>% group_by(id, date) %>% summarize(...)
Similarly if the time window is monthly this is also relatively simple with lubridate: data %>% group_by(id, year(date), month(date)) %>% summarize(...)
However the challenge I'm having is how to setup a time window for an arbitrary period: 5-days, 10-days etc.
There's also the RcppRoll library but both RcppRoll and the rolling functions in zoo seem more setup for regular time series. As far as I can tell these window functions work based on the number of rows instead of a specified time period -- the key difference is that a certain time period might have a differing number of rows depending on date and user.
For example, it's possible for user 1, that the number of transactions in the 5 days previous of 2015-01-01 is equal to 100 transactions and for the same user the number of transactions in the 5 days previous of 2015-02-01 is equal to 5 transactions. Thus looking back a set number of rows will simply not work.
Additionally, there is another SO thread discussing rolling dates for irregular time series type data (Create new column based on condition that exists within a rolling date) however the accepted solution was using data.table and I'm specifically looking for a dplyr way of achieving this.
I suppose at the heart of this issue, this problem can be solved by answering this question: how can I group_by arbitrary time periods in dplyr. Alternatively, if there's a different dplyr way to achieve above without a complicated group_by, how can I do it?
EDIT: updated example to make nature of the rolling window more clear.
This can be done using SQL:
library(sqldf)
dd <- transform(data, date = as.Date(date))
sqldf("select a.*, count(*) n_trans30, sum(b.n_widgets) 'total_widgets30'
from dd a
left join dd b on b.date between a.date - 30 and a.date
and b.id = a.id
and b.rowid <= a.rowid
group by a.rowid")
giving:
id date n_widgets n_trans30 total_widgets30
1 1 2015-01-01 1 1 1
2 1 2015-01-01 2 2 3
3 1 2015-01-05 3 3 6
4 1 2015-01-25 4 4 10
5 2 2015-05-05 5 1 5
6 2 2015-01-01 2 1 2
7 3 2015-08-01 4 1 4
8 4 2015-01-01 5 1 5
Another approach is to expand your dataset to contain all possible days (using tidyr::complete), then use a rolling function (RcppRoll::roll_sum)
The fact that you have multiple observations per day is probably creating an issue though...
library(tidyr)
library(RcppRoll)
df2 <- df %>%
mutate(date=as.Date(date))
## create full dataset with all possible dates (go even 30 days back for first observation)
df_full<- df2 %>%
mutate(date=as.Date(date)) %>%
complete(id,
date=seq(from=min(.$date)-30,to=max(.$date), by=1),
fill=list(n_widgets=0))
## now use rolling function, and keep only original rows (left join)
df_roll <- df_full %>%
group_by(id) %>%
mutate(n_trans_30=roll_sum(x=n_widgets!=0, n=30, fill=0, align="right"),
total_widgets_30=roll_sum(x=n_widgets, n=30, fill=0, align="right")) %>%
ungroup() %>%
right_join(df2, by = c("date", "id", "n_widgets"))
The result is the same as yours (by chance)
id date n_widgets n_trans_30 total_widgets_30
<dbl> <date> <dbl> <dbl> <dbl>
1 1 2015-01-01 1 1 1
2 1 2015-01-01 2 2 3
3 1 2015-01-05 3 3 6
4 1 2015-01-25 4 4 10
5 1 2015-02-15 4 2 8
6 2 2015-05-05 5 1 5
7 2 2015-01-01 2 1 2
8 3 2015-08-01 4 1 4
9 4 2015-01-01 5 1 5
But as said, it will fail for some days as it count last 30 obs, not last 30 days. So you might want first to summarise the information by day, then apply this.
EDITED based on comment below.
You can try something like this for up to 5 days:
df %>%
arrange(id, date) %>%
group_by(id) %>%
filter(as.numeric(difftime(Sys.Date(), date, unit = 'days')) <= 5) %>%
summarise(n_total_widgets = sum(n_widgets))
In this case, there are no days within five of current. So, it won't produce any output.
To get last five days for each ID, you can do something like this:
df %>%
arrange(id, date) %>%
group_by(id) %>%
filter(as.numeric(difftime(max(date), date, unit = 'days')) <= 5) %>%
summarise(n_total_widgets = sum(n_widgets))
Resulting output will be:
Source: local data frame [4 x 2]
id n_total_widgets
(dbl) (dbl)
1 1 4
2 2 5
3 3 4
4 4 5
I found a way to do this while working on this question
df <- data.frame(
id = c(1, 1, 1, 1, 1, 2, 2, 3, 4),
date = c("2015-01-01",
"2015-01-01",
"2015-01-05",
"2015-01-25",
"2015-02-15",
"2015-05-05",
"2015-01-01",
"2015-08-01",
"2015-01-01"),
n_widgets = c(1,2,3,4,4,5,2,4,5)
)
count_window <- function(df, date2, w, id2){
min_date <- date2 - w
df2 <- df %>% filter(id == id2, date >= min_date, date <= date2)
out <- length(df2$date)
return(out)
}
v_count_window <- Vectorize(count_window, vectorize.args = c("date2","id2"))
sum_window <- function(df, date2, w, id2){
min_date <- date2 - w
df2 <- df %>% filter(id == id2, date >= min_date, date <= date2)
out <- sum(df2$n_widgets)
return(out)
}
v_sum_window <- Vectorize(sum_window, vectorize.args = c("date2","id2"))
res <- df %>% mutate(date = ymd(date)) %>%
mutate(min_date = date - 30,
n_trans = v_count_window(., date, 30, id),
total_widgets = v_sum_window(., date, 30, id)) %>%
select(id, date, n_widgets, n_trans, total_widgets)
res
id date n_widgets n_trans total_widgets
1 1 2015-01-01 1 2 3
2 1 2015-01-01 2 2 3
3 1 2015-01-05 3 3 6
4 1 2015-01-25 4 4 10
5 1 2015-02-15 4 2 8
6 2 2015-05-05 5 1 5
7 2 2015-01-01 2 1 2
8 3 2015-08-01 4 1 4
9 4 2015-01-01 5 1 5
This version is fairly case specific but you could probably make a version of the functions that is more general.
For simplicity reasons I recommend runner package which handles sliding window operations. In OP request window size k = 30 and windows depend on date idx = date. You can use runner function which applies any R function on given window, and sum_run
library(runner)
library(dplyr)
df %>%
group_by(id) %>%
arrange(date, .by_group = TRUE) %>%
mutate(
n_trans30 = runner(n_widgets, k = 30, idx = date, function(x) length(x)),
n_widgets30 = sum_run(n_widgets, k = 30, idx = date),
)
# id date n_widgets n_trans30 n_widgets30
#<dbl> <date> <dbl> <dbl> <dbl>
# 1 2015-01-01 1 1 1
# 1 2015-01-01 2 2 3
# 1 2015-01-05 3 3 6
# 1 2015-01-25 4 4 10
# 1 2015-02-15 4 2 8
# 2 2015-01-01 2 1 2
# 2 2015-05-05 5 1 5
# 3 2015-08-01 4 1 4
# 4 2015-01-01 5 1 5
Important: idx = date should be in ascending order.
For more go to documentation and vignettes