You can use the following methods to find the earliest date in a column of a data frame in R:

Method 1: Find Earliest Date in Column

min(df$date_column)

Method 2: Find Row with Earliest Date in Column

df[which.min(df$date), ]

The following examples shows how to use this syntax in practice with the following data frame:

#create data frame
df <- data.frame(date=as.Date(c('2022-04-01','2022-02-12','2022-06-13','2022-02-04',
                                '2022-07-01','2022-02-19','2022-12-03','2022-04-04')),
                 sales = c(12, 15, 24, 24, 14, 19, 12, 38))

#view data frame
df

        date sales
1 2022-04-01    12
2 2022-02-12    15
3 2022-06-13    24
4 2022-02-04    24
5 2022-07-01    14
6 2022-02-19    19
7 2022-12-03    12
8 2022-04-04    38

Example 1: Find Earliest Date in Column

We can use the following code to find the earliest date in the date column of the data frame:

#find earliest date in 'date' column
min(df$date)

[1] "2022-02-04"

From the output we can see that the earliest date in the date column is 2/4/2022.

Note: If you want to find the most recent date, simply change min to max in the code.

Example 2: Find Row with Earliest Date in Column

We can use the following code to find the row with the earliest date in the date column of the data frame:

#find row with earliest date in 'date' column
df[which.min(df$date), ]

        date sales
4 2022-02-04    24

The output displays the entire row that contains the earliest date in the date column.

For example, we can see the following values in this row:

• date: 2022-02-04
• sales: 24

Note: If you want to find the row with the most recent date, simply change which.min() to which.max() in the code.