I want to update an entry for the first duplicate (with respect to an identifier variable) in a data frame with information from the last duplicate. In the data below, I would like the "begin_date" to be the minimum and the "end_date" to be the maximum for that id, while keeping only unique id values.
Change this:
data <- data.frame(id=c(1,1,1,2,2,3,3,3,4,4,4,4),begin_date=c(1970,1976,2000,1969,2010,1950,1986,1990,1960,1968,1972,1983),end_date=c(1976,2000,2012,2010,2013,1986,1990,1999,1968,1972,1983,2001))
To this:
data <- data.frame(id=c(1,2,3,4),begin_date=c(1970,1969,1950,1960),end_date=c(2012,2013,1999,2001))
If you put your data in a data frame, then you can use plyr's ddply for this:
library(plyr)
data <- ddply(data, .(id), summarize, begin_date=min(begin_date),
end_date=max(end_date))
## id begin_date end_date
##1 1 1970 2012
##2 2 1969 2013
##3 3 1950 1999
##4 4 1960 2001
You say it's a data.frame so that is what I constructed:
dat <- data.frame(id=c(1,1,1,2,2,3,3,3,4,4,4,4),
begin_date=c(1970,1976,2000,1969,2010,1950,1986,1990,1960, 1968,1972,1983),
end_date=c(1976,2000,2012,2010,2013,1986,1990,1999,1968, 1972,1983,2001))
with( dat, data.frame(id=unique(id),
begin_date =tapply(begin_date, id, head, 1),
end_date= tapply(end_date, id, tail,1) )
)
id begin_date end_date
1 1 1970 2012
2 2 1969 2013
3 3 1950 1999
4 4 1960 2001
Could also use min and max.
Related
I have a problem when specifying a loop with a data frame.
The general idea I have is the following:
I have an area which contains a certain number of raster quadrants. These raster quadrants have been visited irregularily over several years (e.g. from 1950 -2015).
I have two data frames:
1) a data frame containing the IDs of the rasterquadrants (and one column for the year of first visit of this quadrant):
df1<- as.data.frame(cbind(c("12345","12346","12347","12348"),rep(NA,4)))
df1[,1]<- as.character(df1[,1])
df1[,2]<- as.numeric(df1[,2])
names(df1)<-c("Raster_Q","First_visit")
2) a data frame that contains the infos on the visits; this one is ordered with by 1st rasterquadrants and then 2nd years. This dataframe has the info when the rasterquadrant was visited and when.
df2<- as.data.frame(cbind(c(rep("12345",5),rep("12346",7),rep("12347",3),rep(12348,9)),
c(1950,1952,1955,1967,1951,1968,1970,
1998,2001,2014,2015,2017,1965,1986,2000,1952,1955,1957,1965,2003,2014,2015,2016,2017)))
df2[,1]<- as.character(df2[,1])
df2[,2]<- as.numeric(as.character(df2[,2]))
names(df2)<-c("Raster_Q","Year")
I want to know when and how often the full area was 'sampled'.
Scheme of what I want to do; different colors indicate different areas/regions
My rationale:
I sorted the complete data in df2 according to Quadrant and Year. I then match the rasterquadrant in df1 with the name of the rasterquadrant in df2 and the first value of year from df2 is added.
For this I wrote a loop (see below)
In order not to replicate a quadrant I created a vector "visited"
visited<-c()
Every entry of df2 that matches df1 will be written into this vector, so that the second entry of e.g. rasterquadrant "12345" in df2 is ignored in the loop.
Here comes the loop:
visited<- c()
for (i in 1:nrow(df2)){
index<- which(df1$"Raster_Q"==df2$"Raster_Q"[i])
if(length(index)==0) {next()} else{
if(df1$"Raster_Q"[index] %in% visited){next()} else{
df1$"First_visit"[index]<- df2$"Year"[i]
visited[index]<- df1$"Raster_Q"[index]
}
}
}
This gives me the first full sampling period.
Raster_Q First_visit
1 12345 1950
2 12346 1968
3 12347 1965
4 12348 1952
However, I want to have all full sampling periods.
So I do:
df1$"Second_visit"<-NA
I reset the visited vector and specify the following loop:
visited <- c()
for (i in 1:nrow(df2)){
if(df2$Year[i]<=max(df1$"First_visit")){next()} else{
index<- which(df1$"Raster_Q"==df2$"Raster_Q"[i])
if(length(index)==0) {next()} else{
if(df1$"Raster_Q"[index] %in% visited){next()} else{
df1$"Second_visit"[index]<- df2$"Year"[i]
visited[index]<- df1$"Raster_Q"[index]
}
}
}
}
Which is basically the same loop as before, however, only making sure that, if df2$"Year" in a certain raster quadrant has already been included in the first visit, then it is skipped.
That gives me the second full sampling period:
Raster_Q First_visit Second_visit
1 12345 1950 NA
2 12346 1968 1970
3 12347 1965 1986
4 12348 1952 2003
Okay, so far so good. I could do that all by hand. But I have loads and loads of rasterquadrants and several areas that can and should be screened in this way.
So doing all of this in a single loop for this would be really great! However, I realized that this will create a problem because the loop then gets recursive:
The added column will not be included in the subsequent iteration of the loop, because the df1 itself is not re-read for each loop, and in consequence, the new coulmn for the new sampling period will not be included in the following iterations:
visited<- c()
for (i in 1:nrow(df2)){
m<-ncol(df1)
index<- which(df1$"Raster_Q"==df2$"Raster_Q"[i])
if(length(index)==0) {next()} else{
if(df1$"Raster_Q"[index] %in% visited){next()} else{
df1[index,m]<- df2$"Year"[i]
visited[index]<- df1$"Raster_Q"[index]
#finish "first_visit"
df1[,m+1]<-NA
# add column for "second visit"
if(df2$Year[i]<=max(df1$"First_visit")){next()} else{
# make sure that the first visit year are not included
index<- which(df1$"Raster_Q"==df2$"Raster_Q"[i])
if(length(index)==0) {next()} else{
if(df1$"Raster_Q"[index] %in% visited){next()} else{
df1[index,m+1]<- df2$"Year"[i]
visited[index]<- df1$"Raster_Q"[index]
}
}
}
This won't work. Another issue is that the vector visited() is not emptied during this loop, so that basically every Raster_Q has already been visited in the second sampling period.
I am stuck.... any ideas?
You can do this without a for loop by using the dplyr and tidyr packages. First, you take your df2 and use dplyr::arrange to order by raster and year. Then you can rank the years visited using the rank function inside of the dplyr::mutate function. Then using tidyr::spread you can put them all in their own columns. Here is the code:
df <- df2 %>%
arrange(Raster_Q, Year) %>%
group_by(Raster_Q) %>%
mutate(visit = rank(Year),
visit = paste0("visit_", as.character(visit))) %>%
tidyr::spread(key = visit, value = Year)
Here is the output:
> df
# A tibble: 4 x 10
# Groups: Raster_Q [4]
Raster_Q visit_1 visit_2 visit_3 visit_4 visit_5 visit_6 visit_7 visit_8 visit_9
* <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 12345 1950 1951 1952 1955 1967 NA NA NA NA
2 12346 1968 1970 1998 2001 2014 2015 2017 NA NA
3 12347 1965 1986 2000 NA NA NA NA NA NA
4 12348 1952 1955 1957 1965 2003 2014 2015 2016 2017
EDIT: So I think I understand your problem a little better now. You are looking to remove all duplicate visits to each quadrant that happened before the maximum Year of each respective "round" of visits. So to accomplish this, I wrote a short function that in essence does what the code above does, but with a slight change. Here is the function:
filter_by_round <- function(data, round) {
output <- data %>%
arrange(Raster_Q, Year) %>%
group_by(Raster_Q) %>%
mutate(visit = rank(Year, ties.method = "first")) %>%
ungroup() %>%
mutate(in_round = ifelse(Year <= max(.$Year[.$visit == round]) & visit > round,
TRUE, FALSE)) %>%
filter(!in_round) %>%
select(-c(in_round, visit))
return(output)
}
What this function does, is look through the data and if a given year is less than the max year for the specified "visit round" then it is removed. To apply this only to the first round, you would do this:
df2 %>%
filter_by_round(1) %>%
group_by(Raster_Q) %>%
mutate(visit = rank(Year, ties.method = "first")) %>%
ungroup() %>%
mutate(visit = paste0("visit_", as.character(visit))) %>%
tidyr::spread(key = visit, value = Year)
which would give you this:
# A tibble: 4 x 8
Raster_Q visit_1 visit_2 visit_3 visit_4 visit_5 visit_6 visit_7
* <chr> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 12345 1950 NA NA NA NA NA NA
2 12346 1968 1970 1998 2001 2014 2015 2017
3 12347 1965 1986 2000 NA NA NA NA
4 12348 1952 2003 2014 2015 2016 2017 NA
However, while it does accomplish what your for loop would have, you now have other occurrences of the same problem. I have come up with a way to do this successfully but it requires you to know how many "visit rounds" you had or some trial and error. To accomplish this, you can use map and assign the change to a global variable.
# I do this so we do not lose the original dataset
df <- df2
# I chose 1:5 after some trial and error showed there are 5 unique
# "visit rounds" in your toy dataset
# However, if you overshoot your number, it should still work,
# you will just get warnings about `max` not working correctly
# however, this may casue issues, so figuring out your exact number is
# recommended
purrr::map(1:5, function(x){
# this assigns the output of each iteration to the global variable df
df <<- df %>%
filter_by_round(x)
})
# now applying the original transformation to get the spread dataset
df %>%
group_by(Raster_Q) %>%
mutate(visit = rank(Year, ties.method = "first")) %>%
ungroup() %>%
mutate(visit = paste0("visit_", as.character(visit))) %>%
tidyr::spread(key = visit, value = Year)
This will give you the following output:
# A tibble: 4 x 6
Raster_Q visit_1 visit_2 visit_3 visit_4 visit_5
* <chr> <dbl> <dbl> <dbl> <dbl> <dbl>
1 12345 1950 NA NA NA NA
2 12346 1968 1970 2014 2015 2017
3 12347 1965 1986 NA NA NA
4 12348 1952 2003 2014 2015 2016
granted, this is probably not the most elegant solution, but it works. Hopefully this solves the problem for you
I have data organized by two ID variables, Year and Country, like so:
Year Country VarA VarB
2015 USA 1 3
2016 USA 2 2
2014 Canada 0 10
2015 Canada 6 5
2016 Canada 7 8
I'd like to keep Year as an ID variable, but create multiple columns for VarA and VarB, one for each value of Country (I'm not picky about column order), to make the following table:
Year VarA.Canada VarA.USA VarB.Canada VarB.USA
2014 0 NA 10 NA
2015 6 1 5 3
2016 7 2 8 2
I managed to do this with the following code:
require(data.table)
require(reshape2)
data <- as.data.table(read.table(header=TRUE, text='Year Country VarA VarB
2015 USA 1 3
2016 USA 2 2
2014 Canada 0 10
2015 Canada 6 5
2016 Canada 7 8'))
molten <- melt(data, id.vars=c('Year', 'Country'))
molten[,variable:=paste(variable, Country, sep='.')]
recast <- dcast(molten, Year ~ variable)
But this seems a bit hacky (especially editing the default-named variable field). Can I do it with fewer function calls? Ideally I could just call one function, specifying the columns to drop as IDs and the formula for creating new variable names.
Using dcast you can cast multiple value.vars at once (from data.table v1.9.6 on). Try:
dcast(data, Year ~ Country, value.var = c("VarA","VarB"), sep = ".")
# Year VarA.Canada VarA.USA VarB.Canada VarB.USA
#1: 2014 0 NA 10 NA
#2: 2015 6 1 5 3
#3: 2016 7 2 8 2
My data frame consists of three columns: state name, year, and the tax receipt for each year and each state. Below is an example for just one state.
year RealTaxRevs
1 1971 8335046
2 1972 9624026
3 1973 10498935
4 1974 10052305
5 1975 8708381
6 1976 8911262
7 1977 10759032
I'd like to compute the change in tax receipt from one year to the next, for each state. I used the following code:
data %>% group_by(state) %>% summarise(diff(RealTaxRevs, lag = 1, differences = 1))
but it gives me "Error: expecting a single value".
Could anyone explain this error message, and help me do this correctly using dplyr? Thank you.
If you want to use diff like function, then consider using the zoo library as well. Then you can have code which looks like the following:
library(zoo)
diff(as.zoo(1:4), na.pad=T)
In a data frame setting it would be like:
dat <- data.frame(a=c(8335046, 9624026, 10498935, 10052305, 8708381, 8911262, 10759032))
dat %>% mutate(b=diff(as.zoo(a), na.pad=T))
# a b
# 1 8335046 NA
# 2 9624026 1288980
# 3 10498935 874909
# 4 10052305 -446630
# 5 8708381 -1343924
# 6 8911262 202881
# 7 10759032 1847770
This way you can easily increase the number of lags, without continually adding NA
dat %>% mutate(b2=diff(as.zoo(a), lag=2, na.pad=T))
# a b2
# 1 8335046 NA
# 2 9624026 NA
# 3 10498935 2163889
# 4 NA NA
# 5 8708381 -1790554
# 6 8911262 NA
# 7 10759032 2050651
We can use data.table
library(data.table)
setDT(data)[, Diffs := RealTaxRevs - shift(RealTaxRevs)[[1]], state]
I have a table that looks like the following:
Year Country Variable 1 Variable 2
1970 UK 1 3
1970 USA 1 3
1971 UK 2 5
1971 UK 2 3
1971 UK 1 5
1971 USA 2 2
1972 USA 1 1
1972 USA 2 5
I'd be grateful if someone could tell me how I can aggregate the data to group it first by year, then country with the sum of variable 1 and variable 2 coming afterwards so the output would be:
Year Country Sum Variable 1 Sum Variable 2
1970 UK 1 3
1970 USA 1 3
1971 UK 5 13
1971 USA 2 2
1972 USA 3 6
This is the code I've tried to no avail (the real dataframe is 125,000 rows by 30+ columns hence the subset. Please be kind, I'm new to R!)
#making subset from data
GT2 <- subset(GT1, select = c("iyear", "country_txt", "V1", "V2"))
#making sure data types are correct
GT2[,2]=as.character(GT2[,2])
GT2[,3] <- as.numeric(as.character( GT2[,3] ))
GT2[,4] <- as.numeric(as.character( GT2[,4] ))
#removing NA values
GT2Omit <- na.omit(GT2)
#trying to aggregate - i.e. group by year, then country with the sum of Variable 1 and Variable 2 being shown
aggGT2 <-aggregate(GT2Omit, by=list(GT2Omit$iyear, GT2Omit$country_txt), FUN=sum, na.rm=TRUE)
Your aggregate is almost correct:
> aggGT2 <-aggregate(GT2Omit[3:4], by=GT2Omit[c("country_txt", "iyear")], FUN=sum, na.rm=TRUE)
> aggGT2
country_txt iyear V1 V2
1 UK 1970 1 3
2 USA 1970 1 3
3 UK 1971 5 13
4 USA 1971 2 2
5 USA 1972 3 6
dplyr is almost always the answer nowadays.
library(dplyr)
aggGT1 <- GT1 %>% group_by(iyear, country_txt) %>% summarize(sv1=sum(V1), sv2=sum(V2))
Having said that, it is good to learn basic R functions like aggregate and by.
I have a data frame with columns year|country|growth_rate. I wanted to to find country with highest growth rate in every year, which I did with:
ddply(data, .(year), summarise, highest=max(growth_rate))
and I've got data frame with 2 columns; year and highest
I would like to add third column here, which would show that country that had that max growth_rate, but I can't figure out how to do this.
R> data = data.frame(year = rep(1990:1993, 2), growth_rate = runif(8), country = rep(c("US", "FR"), each = 4))
R> data
year growth_rate country
1 1990 0.82785327 US
2 1991 0.86724498 US
3 1992 0.84813164 US
4 1993 0.35884355 US
5 1990 0.92792399 FR
6 1991 0.08659153 FR
7 1992 0.26732516 FR
8 1993 0.37819132 FR
R> ddply(data, .(year), summarize, highest = max(growth_rate), country = country[which.max(growth_rate)])
year highest country
1 1990 0.9279240 FR
2 1991 0.8672450 US
3 1992 0.8481316 US
4 1993 0.3781913 FR