如何使用lubridate在R中将多列转换为日期格式？

Question

I have a database with multiple columns of dates as character class. I want to use the lubridate package in R to convert them all at once. I'm not having trouble parsing the date format, but in applying lubridate over multiple columns. Any suggestions?

crimes.df <- data.frame(offense.date = c('06102003', '05122006'), charge.date = c('07152003', '10012010'))

I have tried

crimes.df[,1:2]<-mdy(crimes.df[,1:2])

and

crimes.df[,1:2]<-lapply(crimes.df[,1:2], function(x) mdy(crimes.df[,1:2]))

both return this error:

Warning message:
All formats failed to parse. No formats found. 

(and, inconveniently, wipe out all data in the columns.)

Answer 1

Using lapply , we are looping the columns of the dataset and the function mdy is applied on each column .

crimes.df[] <- lapply(crimes.df, mdy)

---

In the OP's code, if we are calling the anonymous function ( function(x) ), then the function ( mdy ) should be applied on 'x'

crimes.df[] <- lapply(crimes.df, function(x) mdy(x))

Also, note that since there are only 2 columns, we don't need to specify the crimes.df[,1:2]