This is the information contained within my dataframe:
## minuteofday: factor w/ 89501 levels "2013-06-01 08:07:00",...
## dDdt: num 7.8564 2.318 ...
## minutes: POSIXlt, format: NA NA NA
I need to convert the minute of day column to a date/time format:
minuteave$minutes <- as.POSIXlt(as.character(minuteave$minuteofday), format="%m/%d/%Y %H:%M:%S")
I've tried as.POSIXlt, as.POSIXct and as.Date. None of which worked. Does anyone have ANY thoughts.
The goal is to plot minutes vs. dDdt, but it won't let me plot in the specified time period that I want to as a factor. I have no idea what to try next...
You need to insert an as.character() before parsing as a Datetime or Date.
A factor will always come back first as a number corresponding to its level.
You can save the conversion from factor to character by telling read.csv() etc to no store as a factor: stringsAsFactors=FALSE. You can also set that as a global option.
Once you have it as character, make sure you match the format string to your data:
R> as.POSIXct("2013-06-01 08:07:00", format="%Y-%m-%d %H:%M:%S")
[1] "2013-06-01 08:07:00 CDT"
R>
Note the %Y-%m-%d I used, as opposed to your %m/%d/%y.
Edit on 3 Jan 2016: This is now much easier thanks to the anytime package which automagically converts from many types, including factor, and does so without requiring a format string.
R> as.factor("2013-06-01 08:07:00")
[1] 2013-06-01 08:07:00
Levels: 2013-06-01 08:07:00
R>
R> library(anytime)
R> anytime(as.factor("2013-06-01 08:07:00"))
[1] "2013-06-01 08:07:00 CDT"
R>
R> class(anytime(as.factor("2013-06-01 08:07:00")))
[1] "POSIXct" "POSIXt"
R>
As you can see we just feed the factor variable into anytime() and out comes the desired POSIXct type.
Try this
library(lubridate)
minuteave$minutes <- ymd_hms(minuteave$minutes)
this will return minuteave$minutes as a POSIXct object.
Hope this helps you.
Related
I have a large dataframe with a column containing date-times, encoded as a factor variable.My Sys.timezone() is "Europe/Berlin". The date-times have this format:
2015-05-05 17:27:04+05:00
where +05:00 represents the timeshift from GMT. Importantly, I have multiple timezones in my dataset, so I cannot set a specific timezone and ignore the last 6 characters of the strings. This is what I tried so far:
# Test Date
test <- "2015-05-05 17:27:04+05:00"
# Removing the ":" to make it readable by %z
A <- paste(substr(test,1,22),substr(test,24,25),sep = "");A
# Returns
# "2015-05-05 17:27:04+0500"
output <- as.POSIXct(as.character(A, "%Y-%B-%D %H:%M:%S%z"))
# Returns
# "2015-05-05 17:27:04 CEST"
The output of "CEST" for +0500 is incorrect. Moreover, when I run this code on the whole column I see that every date is coded as CEST, regardless of the offset.
How can I keep the specified timezone when converting to POSIXct?
In order to facilitate the process you can use lubridate package.
E.g.
library("lubridate")#load the package
ymd_hms("2015-05-05 17:27:04+05:00",tz="GMT")#set the date format
[1] "2015-05-05 12:27:04 GMT"
Therefore you keep the timezone info. Finally:
as.POSIXct(ymd_hms("2015-05-05 17:27:04+05:00",tz="GMT"),tz = "GMT")#transform the date into another timezone
[1] "2015-05-05 12:27:04 GMT"
I need to convert a string of dates that is in multiple formats to valid dates.
e.g.
dates <- c("01-01-2017","02-01-2017","12-01-2016","20160901","20161001", "20161101")
> as.Date(dates, format=c("%m-%d-%Y","%Y%m%d"))
[1] "2017-01-01" NA "2016-12-01" "2016-09-01" NA "2016-11-01"
two dates show as NA
This is pretty much I wrote the anytime package for:
R> dates <- c("01-01-2017","02-01-2017","12-01-2016","20160901","20161001",
+ "20161101")
R> library(anytime)
R> anydate(dates)
[1] "2017-01-01" "2017-02-01" "2016-12-01" "2016-09-01"
[5] "2016-10-01" "2016-11-01"
R>
Parse any sane input reliably and without explicit format or origin or other line noise.
That being said, not starting ISO style with the year is asking for potential trouble, so 02-03-2017 could be February 3 or March 2. I am following the North American convention I too consider somewhat broken -- but is so darn prevalent. Do yourself a favour and try to limit inputs to ISO dates, at least ISO order YYYYMMDD.
I have tried library(anytime), however for big data did not work.
Then, I found useful this sequence:
df$Date2 <- format(as.Date(df$Date, format="%m/%d/%Y"), "%d/%m/%y")
df$Date2 <- as.Date(df$Date2,"%d/%m/%y")
It worked for me to "8/10/2005" as well as "08/13/05" in the same column.
I have a file with nearly four thousand entries in a column formatted like this:
1/28/2015 14:13
How do I get R to read these as real numbers?
As #RomanLuštrik suggested:
mydate <- "1/28/2015 14:13"
# convert to date
strptime(mydate, "%m/%d/%Y %H:%M")
# [1] "2015-01-28 14:13:00 GMT"
# make it numeric
as.numeric(strptime(mydate, "%m/%d/%Y %H:%M"))
# [1] 1422454380
datestring<-"your variable"
x<-strptime(datestring, %b/%d,%Y %H:%M)
Just check out the strptime() info
there is the lubridate package with a lot of functions for this for changing formats
for real numbers you have POSIXct() function.
This is the information contained within my dataframe:
## minuteofday: factor w/ 89501 levels "2013-06-01 08:07:00",...
## dDdt: num 7.8564 2.318 ...
## minutes: POSIXlt, format: NA NA NA
I need to convert the minute of day column to a date/time format:
minuteave$minutes <- as.POSIXlt(as.character(minuteave$minuteofday), format="%m/%d/%Y %H:%M:%S")
I've tried as.POSIXlt, as.POSIXct and as.Date. None of which worked. Does anyone have ANY thoughts.
The goal is to plot minutes vs. dDdt, but it won't let me plot in the specified time period that I want to as a factor. I have no idea what to try next...
You need to insert an as.character() before parsing as a Datetime or Date.
A factor will always come back first as a number corresponding to its level.
You can save the conversion from factor to character by telling read.csv() etc to no store as a factor: stringsAsFactors=FALSE. You can also set that as a global option.
Once you have it as character, make sure you match the format string to your data:
R> as.POSIXct("2013-06-01 08:07:00", format="%Y-%m-%d %H:%M:%S")
[1] "2013-06-01 08:07:00 CDT"
R>
Note the %Y-%m-%d I used, as opposed to your %m/%d/%y.
Edit on 3 Jan 2016: This is now much easier thanks to the anytime package which automagically converts from many types, including factor, and does so without requiring a format string.
R> as.factor("2013-06-01 08:07:00")
[1] 2013-06-01 08:07:00
Levels: 2013-06-01 08:07:00
R>
R> library(anytime)
R> anytime(as.factor("2013-06-01 08:07:00"))
[1] "2013-06-01 08:07:00 CDT"
R>
R> class(anytime(as.factor("2013-06-01 08:07:00")))
[1] "POSIXct" "POSIXt"
R>
As you can see we just feed the factor variable into anytime() and out comes the desired POSIXct type.
Try this
library(lubridate)
minuteave$minutes <- ymd_hms(minuteave$minutes)
this will return minuteave$minutes as a POSIXct object.
Hope this helps you.
I am trying to convert the date as factor to date using “as.date” function in R. I have the date in the following format
2008-01-01 02:30
I tried to use the following command :
as.Date(mydata$Date, format="%y-%m-%d %h:%mm")
Can somebody help me with this ? I was able to convert the format with no hour but getting difficulty with hour included.
Thank you.
Your format string is incorrect :
R> strptime("2008-01-01 02:30", format="%Y-%m-%d %H:%M")
# [1] "2008-01-01 02:30:00"
See ?strptime for the detailed values you can use to define a format.
Also note that as your string is in a standard format, you can also use directly as.POSIXlt :
R> as.POSIXlt("2008-01-01 02:30")
# [1] "2008-01-01 02:30:00"