Filtering rows in a data frame based on date column

Question

I have the following data frame:

id        day           total_amount
 1       2016-06-09         1000
 1       2016-06-23          100
 1       2016-06-24          200
 1       2015-11-27         2392
 1       2015-12-16          123
 7       2015-07-09          200
 7       2015-07-09         1000
 7       2015-08-27       100018
 7       2015-11-25         1000

How can I throw away rows where day column is older than three weeks from today using both base R packages and other packages such as dplyr .

akrun · Accepted Answer · 2016-06-27 06:48:27Z

3

We can use subset

 subset(df1, as.Date(day) > Sys.Date()-21)

edited Jun 27, 2016 at 6:48

answered Jun 27, 2016 at 6:31

akrun

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2 Comments

chessosapiens Over a year ago

subset(test_df, as.Date(day) > Sys.Date()-21) seems to be correct ,what is your idea?

akrun Over a year ago

@sanaz Corrected that. I thought it was the other way. Sorry

lmo · Accepted Answer · 2016-06-27 12:50:41Z

Just to fill in two additional possibilities (that are nearly identical to one another in terms of syntax and quite similar to @akrun's use of subset).

You can use with in as follows to shorten the number of characters:

with(df, df[as.Date(day) > Sys.Date()-21,])

As you mentioned a desire to see other packages, here is one way to drop old observations using the data.table package.

library(data.table)
# turn df into a data.table
setDT(df)

df[as.Date(day) > Sys.Date()-21,]

data

df <- read.table(header=T, text="id        day           total_amount
 1       2016-06-09         1000
 1       2016-06-23          100
 1       2016-06-24          200
 1       2015-11-27         2392
 1       2015-12-16          123
 7       2015-07-09          200
 7       2015-07-09         1000
 7       2015-08-27       100018
 7       2015-11-25         1000")

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