How to compute the daily average from hourly values? - r

I have a text file consisting of 6 columns as shown below. the measurements are taken each 30 mint for several years (2001-2013). I want to compute the daily average so for example: for 2001 take all values correspond to the first day (1) and compute the average and do this for all days in that year and also for all years available in the text file.
to read the file:
LR=read.table("C:\\Users\\dat.txt", sep ='', header =TRUE)
header:
head(LR)
Year day hour mint valu1 valu2
1 2001 1 5 30 0 0
2 2001 1 6 0 1 0
3 2001 1 6 30 2 0
4 2001 1 7 0 0 7
5 2001 1 7 30 5 8
6 2001 1 8 0 0 0

Try:
library(plyr)
ddply(LR, .(Year, day), summarize, val = mean(valu1))
And another less elegant option:
LR$n <- paste(LR$Year, LR$day, sep="-")
tapply(LR$valu1, LR$n, FUN=mean)
If you want to select a certain range of years use subset:
dat < ddply(LR, .(Year, day), summarize, val = mean(valu1))
subset(dat, Year > 2003 & Year < 2005)

You can try aggregate:
res <- aggregate(LR, by = list(paste0(dat$Year, dat$day)), FUN = mean)
## You can remove the extra columns if you want
res[, -c(1,4,5)]
Or as Michael Lawrence suggests, using the formula interface:
aggregate(cbind(valu1, valu2) ~ Year + day, LR, mean)

Related

Calculating age per animal by subtracting years in R

I am looking to calculate relative age of animals. I need to subtract sequentially each year from the next for each animal in my dataset. Because an animal can have multiple reproductive events in a year, I need the age for the remaining events in that year (i.e. all events after the first) to be the same as the initial calculation.
Update:
The dataset more resembles this:
Year ID Age
1 1975 6 -1
2 1975 6 -1
3 1976 6 -1
4 1977 6 -1
6 1975 9 -1
8 1978 9 -1
And I need it to look like this
Year ID Age
1 1975 6 0
2 1975 6 0
3 1976 6 1
4 1977 6 2
6 1975 9 0
8 1978 9 3
Apologies for the initial confusion, if I wasn't clear on what I needed to accomplish.
Any help would be greatly appreciated.
Things done "by group" are usually easiest to do using dplyr or data.table
library(dplyr)
your_data %>%
group_by(ID) %>% # group by ID
mutate(Age = Year - min(Year)) # add new column
or
library(data.table)
setDT(your_data) # convert to data table
# add new column by group
your_data[, Age := Year - min(Year), by = ID]
In base R, ave is probably easiest for adding a groupwise columns to existing data:
your_data$Age = with(your_data, ave(Year, ID, function(x) x - min(x)))
but the syntax isn't as nice as the options above.
You can test on this data:
your_data = read.table(text = " Year ID Age
1 1975 6 -1
2 1975 6 -1
3 1976 6 -1
4 1977 6 -1
6 1975 9 -1
8 1978 9 -1 ", header = T)
if you're trying to figure out the relative age based on one intial birth year, 1975 (which it seems like you are), then you can just make a new column called "RelativeAge" and set it equal to the year - 1975
data$RelativeAge = (Year-1975)
then just get rid of the original "Age" column, or rename as necessary

Aggregation on 2 columns while keeping two unique R

So I have this:
Staff Result Date Days
1 50 2007 4
1 75 2006 5
1 60 2007 3
2 20 2009 3
2 11 2009 2
And I want to get to this:
Staff Result Date Days
1 55 2007 7
1 75 2006 5
2 15 2009 5
I want to have the Staff ID and Date be unique in each row, but I want to sum 'Days' and mean 'Result'
I can't work out how to do this in R, I'm sure I need to do lots of aggregations but I keep getting different results to what I am aiming for.
Many thanks
the simplest way to do this is to group_by Staff and Date and summarise the results with dplyr package:
require(dplyr)
df <- data.frame(Staff = c(1,1,1,2,2),
Result = c(50, 75, 60, 20, 11),
Date = c(2007, 2006, 2007, 2009, 2009),
Days = c(4, 5, 3, 3, 2))
df %>%
group_by(Staff, Date) %>%
summarise(Result = floor(mean(Result)),
Days = sum(Days)) %>%
data.frame
Staff Date Result Days
1 1 2006 75 5
2 1 2007 55 7
3 2 2009 15 5
You can aggregate on two variables by using a formula and then merge the two aggregates
merge(aggregate(Result ~ Staff + Date, data=df, mean),
aggregate(Days ~ Staff + Date, data=df, sum))
Staff Date Result Days
1 1 2006 75.0 5
2 1 2007 55.0 7
3 2 2009 15.5 5
Here is another option with data.table
library(data.table)
setDT(df1)[, .(Result = floor(mean(Result)), Days = sum(Days)), .(Staff, Date)]
# Staff Date Result Days
#1: 1 2007 55 7
#2: 1 2006 75 5
#3: 2 2009 15 5

(In)correct use of a linear time trend variable, and most efficient fix?

I have 3133 rows representing payments made on some of the 5296 days between 7/1/2000 and 12/31/2014; that is, the "Date" feature is non-continuous:
> head(d_exp_0014)
Year Month Day Amount Count myDate
1 2000 7 6 792078.6 9 2000-07-06
2 2000 7 7 140065.5 9 2000-07-07
3 2000 7 11 190553.2 9 2000-07-11
4 2000 7 12 119208.6 9 2000-07-12
5 2000 7 16 1068156.3 9 2000-07-16
6 2000 7 17 0.0 9 2000-07-17
I would like to fit a linear time trend variable,
t <- 1:3133
to a linear model explaining the variation in the Amount of the expenditure.
fit_t <- lm(Amount ~ t + Count, d_exp_0014)
However, this is obviously wrong, as t increments in different amounts between the dates:
> head(exp)
Year Month Day Amount Count Date t
1 2000 7 6 792078.6 9 2000-07-06 1
2 2000 7 7 140065.5 9 2000-07-07 2
3 2000 7 11 190553.2 9 2000-07-11 3
4 2000 7 12 119208.6 9 2000-07-12 4
5 2000 7 16 1068156.3 9 2000-07-16 5
6 2000 7 17 0.0 9 2000-07-17 6
Which to me is the exact opposite of a linear trend.
What is the most efficient way to get this data.frame merged to a continuous date-index? Will a date vector like
CTS_date_V <- as.data.frame(seq(as.Date("2000/07/01"), as.Date("2014/12/31"), "days"), colnames = "Date")
yield different results?
I'm open to any packages (using fpp, forecast, timeSeries, xts, ts, as of right now); just looking for a good answer to deploy in functional form, since these payments are going to be updated every week and I'd like to automate the append to this data.frame.
I think some kind of transformation to regular (continuous) time series is a good idea.
You can use xts to transform time series data (it is handy, because it can be used in other packages as regular ts)
Filling the gaps
# convert myDate to POSIXct if necessary
# create xts from data frame x
ts1 <- xts(data.frame(a = x$Amount, c = x$Count), x$myDate )
ts1
# create empty time series
ts_empty <- seq( from = start(ts1), to = end(ts1), by = "DSTday")
# merge the empty ts to the data and fill the gap with 0
ts2 <- merge( ts1, ts_empty, fill = 0)
# or interpolate, for example:
ts2 <- merge( ts1, ts_empty, fill = NA)
ts2 <- na.locf(ts2)
# zoo-xts ready functions are:
# na.locf - constant previous value
# na.approx - linear approximation
# na.spline - cubic spline interpolation
Deduplicate dates
In your sample there is now sign of duplicated values. But based on a new question it is very likely. I think you want to aggregate values with sum function:
ts1 <- period.apply( ts1, endpoints(ts1,'days'), sum)

How to represent two columns of year and day as a date?

I have a text file consisting of 3 columns as shown below. the measurements are taken each day for several years (2001-2013). I want to plot a time series for valu1 but as the year and day are separated I have a problem:
to read the file:
LR=read.table("C:\\Users\\dat.txt", sep ='', header =TRUE)
header:
head(LR)
Year day valu1
1 2001 1 0
2 2001 2 1
3 2001 3 2
4 2001 4 0
5 2001 5 0.30
6 2001 6 0
I tried this:
LR$Year=as.Date(as.character(LR$Year))
Error in `$<-.data.frame`(`*tmp*`, "Year", value = numeric(0)) :
replacement has 0 rows, data has .
I do not know if all days are available so I wonder if we can tell R that if a date is missing, just replace it with NA but still consider the missing date in the plot with no value in the plot.
You can try:
LR$date <- as.Date(paste(LR$Year, LR$day, sep = "-"), format = "%Y-%j")
I assumed here that day is the day of the year, so something that goes from 1 - 366. This is the %j in the format.

writing the outcome of a nested loop to a vector object in R

I have the following data read into R as a data frame named "data_old":
yes year month
1 15 2004 5
2 9 2005 6
3 15 2006 3
4 12 2004 5
5 14 2005 1
6 15 2006 7
. . ... .
. . ... .
I have written a small loop which goes through the data and sums up the yes variable for each month/year combination:
year_f <- c(2004:2006)
month_f <- c(1:12)
for (i in year_f){
for (j in month_f){
x <- subset(data_old, month == j & year == i, select="yes")
if (nrow(x) > 0){
print(sum(x))
}
else{print("Nothing")}
}
}
My question is this: I can print the sum for each month/year combination in the terminal, but how do i store it in a vector? (the nested loop is giving me headaches trying to figure this out).
Thomas
Another way,
library(plyr)
ddply(data_old,.(year,month),function(x) sum(x[1]))
year month V1
1 2004 5 27
2 2005 1 14
3 2005 6 9
4 2006 3 15
5 2006 7 15
Forget the loops, you want to use an aggregation function. There's a recent discussion of them in this SO question.
with(data_old, tapply(yes, list(year, month), sum))
is one of many solutions.
Also, you don't need to use c() when you aren't concatenating anything. Plain 1:12 is fine.
Just to add a third option:
aggregate(yes ~ year + month, FUN=sum, data=data_old)

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