从“月/年”格式的字符串中生成日期

Question

I have the following date and it's in a 'month-year' format. However, to plot the dates on the x-axis of a ggplot2 graphic, I'm trying to convert them into a date format. With the as.Date function, it produces NA values because no 'day' value is provided. So beyond pasting the day into each date using the paste() function, how can I handle adjusting the dates so that I can plot them.

date = c("Jan-10","Feb-10","Mar-10","Jun-10","Jul-10")
date

date = as.Date(date, "%m/%d/%Y")   # doesn't work
date = as.Date(as.yearmon(date, format="%y-%b"))  # doesn't work

Thanks!

Answer 1

You've got it backwards:

library(zoo)
as.yearmon(date, format="%b-%y")
# [1] "Jan 2010" "Feb 2010" "Mar 2010" "Jun 2010" "Jul 2010"

Specify the format in the order in which it appears in the input.

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Do not just arbitrarily specify the date format. Note what your attempts were looking for:

• "%m/%d/%Y" does not work because that is expecting dates in the form of "10/31/2013"
• "%y-%b" does not work because that is expecting dates in the form of "13-Oct"