R - conversion from chr to POSIXct date/time format in imported csv file ends in N/A -

i have imported csv file (excel) timestamp , value. efforts convert timestamp column usable time in r result in n/a. have looked @ several threads (so , elsewhere) , tried many suggestions somehow not managed right. have tried various simpler examples e.g. r-bloggers , have worked fine.

> dframe <- read.csv2("file.csv", dec=".", colclasses=c("character","numeric"), as.is=true)

> str(dframe)

    'data.frame':   424 obs. of  2 variables:      $ d: chr  "2016.08.02 03:59:45" "2016.08.02 04:11:16" "2016.08.02 04:22:45" "2016.08.02 04:34:13" ...      $ h: num  30 33.3 35.6 35.6 48.9 48.9 48.9 47.8 46.7 46.7 ... 

this believe start. then:

> dframe$d <- as.posixct(dframe$d, tz="gmt", format="%y.%m.%d %h:%m:%s")
> str(dframe)

    'data.frame':   424 obs. of  2 variables:      $ d: posixct, format: na na na na ...      $ h: num  30 33.3 35.6 35.6 48.9 48.9 48.9 47.8 46.7 46.7 ... 

any suggestions welcome. aware of lubridate not trying it, while @ least.

try lubridate

multithreaded blas/lapack libraries detected. using 8 cores math algorithms. > library(lubridate)  attaching package: ‘lubridate’  following object masked ‘package:base’:      date  > ymd_hms("2016.08.02 03:59:45") [1] "2016-08-02 03:59:45 utc" > str(ymd_hms("2016.08.02 03:59:45")) posixct[1:1], format: "2016-08-02 03:59:45" 

"i aware of lubridate not trying it, while @ least." -- there reason not want to/can't use lubridate? seems easy fix.

edit

i bored @ work today, decided give shot. reason posixct function failed because of "." have seperators. quick fix use gsub replace "." "-". here example:

> s = c("2016.08.02 03:59:45", "2016.08.02 04:11:16", "2016.08.02 04:22:45", "2016.08.02 04:34:13") > dates = as.posixct(gsub(pattern="\\.", replacement="-", x=s))  > print(dates) [1] "2016-08-02 03:59:45 pdt" "2016-08-02 04:11:16 pdt" [3] "2016-08-02 04:22:45 pdt" "2016-08-02 04:34:13 pdt"