CODEWITHSUNDEEP
r
user1471980
user1471980

Reputation: 10626

how do you convert times to POSIX times in R

I have this data frame:

dput(df)

structure(list(Time = structure(1:20, .Label = c("1/29/15 9:20 PM", 
"1/29/15 9:30 AM", "1/29/15 9:30 PM", "1/29/15 9:40 AM", "1/29/15 9:40 PM", 
"1/29/15 9:50 AM", "1/29/15 9:50 PM", "1/30/15 1:00 AM", "1/30/15 1:10 AM", 
"1/30/15 1:20 AM", "1/30/15 1:30 AM", "1/30/15 1:40 AM", "1/30/15 1:50 AM", 
"1/30/15 12:00 AM", "1/30/15 12:10 AM", "1/30/15 12:20 AM", "1/30/15 12:30 AM", 
"1/30/15 12:40 AM", "1/30/15 12:50 AM", "1/30/15 2:00 AM"), class = "factor"), 
    Server1 = c(0, 0.5, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
    0, 0, 0, 0, NA)), .Names = c("Time", "Server1"), class = "data.frame", row.names = c(NA, 
-20L))

I need to convert df$Time as POSIXct. I am doing this:

df$Time<-as.POSIXct(df$Time, format="%m/%d/%y %H:%M %p", tz="America/New_York")

this value: 1/30/15 12:50 AM becomes

2015-01-30 12:50:00, not AM but PM. Any ideas how could I convert this 12:50 AM and similar dates to AM not PM?

Upvotes: 0

Views: 82

Answers (2)

Joshua Ulrich
Joshua Ulrich

Reputation: 176648

In the Details section of ?strptime, in the section for "%p", it says, "Used in conjunction with "%I" and not with "%H". So it works if you do that.

d <- structure(list(Time = structure(1:20, .Label = c("1/29/15 9:20 PM", 
"1/29/15 9:30 AM", "1/29/15 9:30 PM", "1/29/15 9:40 AM", "1/29/15 9:40 PM", 
"1/29/15 9:50 AM", "1/29/15 9:50 PM", "1/30/15 1:00 AM", "1/30/15 1:10 AM", 
"1/30/15 1:20 AM", "1/30/15 1:30 AM", "1/30/15 1:40 AM", "1/30/15 1:50 AM", 
"1/30/15 12:00 AM", "1/30/15 12:10 AM", "1/30/15 12:20 AM", "1/30/15 12:30 AM", 
"1/30/15 12:40 AM", "1/30/15 12:50 AM", "1/30/15 2:00 AM"), class = "factor"), 
    Server1 = c(0, 0.5, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
    0, 0, 0, 0, NA)), .Names = c("Time", "Server1"), class = "data.frame",
 row.names = c(NA, -20L))
d$Time <- as.POSIXct(d$Time, format="%m/%d/%y %I:%M %p", tz="America/New_York")

Upvotes: 3

Frank P.
Frank P.

Reputation: 513

Use the lubridate package.

library(lubridate)
time$Time <- mdy_hm(time$Time)

To check:

> str(time)
'data.frame':   20 obs. of  2 variables:
 $ Time   : POSIXct, format: "2015-01-29 21:20:00" "2015-01-29 09:30:00" "2015-01-29 21:30:00" "2015-01-29 09:40:00" ...
 $ Server1: num  0 0.5 0 1 0 0 0 0 0 0 ...

Upvotes: -1

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