Question

I have a datset where I have data from 1997 to 2009 and I want to subset the data according to date.

The code I have written is as follows:

creek <- read.csv("wolfcreek.csv")
library(ggplot2)
creek[1:10,]
colnames(creek) <- c("date","flow")
creek$date <- as.Date(creek$date, "%m/%d/%Y")

The code I used to create the subset is as follows:

creek1 <- subset(creek, as.Date(date) > (01-01-2000) & as.Date(date) <(01-01-2009))

But when I try to see the summary of creek1 I get

> creek1
[1] date flow
<0 rows> (or 0-length row.names)

Can anyone tell what I did wrong here ?

The dataset I used can be found on https://www.dropbox.com/s/eqpena3nk82x67e/creek.csv

Thank you so much.

Best Regards,
Jdbaba

Answer 1

No need to convert the column date, it is already in on the class Date.
Then you need to cretae dateMin, and dateMax coercing a string to a date.

Here I give the string in the right format, otherwise you need to use format (like in @Mathew answer)

subset(creek, date > as.Date("2000-01-01") & date < as.Date("2009-01-01"))

Here, I would use package xts for his fast subsetting and concise syntax

library(xts)
dat.xts <- as.xts(creek$flow, order.by=creek$date)
dat.xts['2000-01/2009-01'] ## powerful and fast!!

using quantmod for example, It is time series so wee need to use the suitable package to treat it.
Here I subset, and I plot (I zoom my time series)

 chart_Series(dat.xts['2000-01/2000-09'])