R更改月份/合并日期和年份向量

Question

I have a dataset that has three columns: month, day, and year. The month is a character vector and shows the month name in full. The day and year vectors are both numeric. I need to convert the month names to their respective number and then combine all three columns to make a full date ("mm-dd-yy"). I have tried to use lubridate, but have not had success. Here is an example of my dataset:

Month      Day      Year
JANUARY    1        1980

Thanks.

Answer 1

You could try

v1 <-  do.call(paste, df1)
as.Date(v1, '%B %d %Y')

Or using lubridate

library(lubridate)
mdy(v1)

Or

 mdy(sprintf('%s %s %s', df1$Month, df1$Day, df1$Year))

Or you can use do.call with sprintf

 mdy(do.call(sprintf, c(df1, list('%s %s %s'))))

Answer 2

this works:

your data example :

df<-(read.table(text="
Month Day Year 
JANUARY 1 1980", header=T))



as.Date(paste(df$Month, df$Day, df$Year), format="%b %d %Y")

#"1980-01-01"

Answer 3

Since you already have the month/day/year separated into separate fields, straight up string manipulation may be a bit faster than converting to time/date classes and back:

MONTHS <- c('JANUARY',
'FEBRUARY',
'MARCH',
'APRIL',
'MAY',
'JUNE',
'JULY',
'AUGUST',
'SEPTEMBER',
'OCTOBER',
'NOVEMBER',
'DECEMBER')

library(stringr)
paste(str_pad(paste(match(myData$Month,MONTHS)), 2, side = "left", pad = "0"),
      str_pad(myData$Day, 2, side = "left", pad = "0"),
      substr(myData$Year,3,4),
      sep = '-')