sdate<-as.POSIXct(strptime(date,format="%m/%d/%Y %H:%M"))

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Newbie here~

I've spent a ton of time on this, but have to admit I am stuck.  I've tried various combinations of strptime and the package CHRON, but still can't get there.

My simple task is that I want to plot salinity (S1 or S2) on y-axis and time on x-axis, but I want to use a lay-understandable representation of time (not Julian).  If I use the following command, I can make a plot using "plot(S1~sdate)", where:

sdate<-as.POSIXct(strptime(date,format="%m/%d/%Y %H:%M"))

... however, every 00:00 time winds up being an NA.  Here is an excerpt of the input data (this is a HUGE file):

index                        Date       Julian         S1      S2
24985       11/19/2006 00:00 39040.01 20.40 22.11  (this line winds up being an NA)
24986       11/19/2006 01:00 39040.05 20.42 22.22
24987       11/19/2006 02:00 39040.09 20.60 22.29
24988       11/19/2006 03:00 39040.14 20.62 22.21
24989       11/19/2006 04:00 39040.18 20.75 22.39

... an excerpt of the variable "sdate" winds up looking like this:

[35017] NA                        "2007-09-08 01:00:00 EDT"
[35019] "2007-09-08 01:00:00 EDT" "2007-09-08 10:00:00 EDT"
[35021] "2007-09-08 10:00:00 EDT" "2007-09-08 11:00:00 EDT"
[35023] "2007-09-08 11:00:00 EDT" "2007-09-08 12:00:00 EDT"
[35025] "2007-09-08 02:00:00 EDT" "2007-09-08 02:00:00 EDT"
[35027] "2007-09-08 03:00:00 EDT" "2007-09-08 03:00:00 EDT"
[35029] "2007-09-08 04:00:00 EDT" "2007-09-08 04:00:00 EDT"
[35031] "2007-09-08 05:00:00 EDT" "2007-09-08 05:00:00 EDT"
[35033] "2007-09-08 06:00:00 EDT" "2007-09-08 06:00:00 EDT"
[35035] "2007-09-08 07:00:00 EDT" "2007-09-08 07:00:00 EDT"
[35037] "2007-09-08 08:00:00 EDT" "2007-09-08 08:00:00 EDT"
[35039] "2007-09-08 09:00:00 EDT" "2007-09-08 09:00:00 EDT"
[35041] NA                        "2007-09-09 01:00:00 EDT"
[35043] "2007-09-09 01:00:00 EDT" "2007-09-09 10:00:00 EDT"
[35045] "2007-09-09 10:00:00 EDT" "2007-09-09 11:00:00 EDT"
[35047] "2007-09-09 11:00:00 EDT" "2007-09-09 12:00:00 EDT"
[35049] "2007-09-09 02:00:00 EDT" "2007-09-09 02:00:00 EDT"
[35051] "2007-09-09 03:00:00 EDT" "2007-09-09 03:00:00 EDT"
[35053] "2007-09-09 04:00:00 EDT" "2007-09-09 04:00:00 EDT"
[35055] "2007-09-09 05:00:00 EDT" "2007-09-09 05:00:00 EDT"
[35057] "2007-09-09 06:00:00 EDT" "2007-09-09 06:00:00 EDT"
[35059] "2007-09-09 07:00:00 EDT" "2007-09-09 07:00:00 EDT"
[35061] "2007-09-09 08:00:00 EDT" "2007-09-09 08:00:00 EDT"
[35063] "2007-09-09 09:00:00 EDT" "2007-09-09 09:00:00 EDT"

Gregory A. Graves
Lead Scientist
RECOVER Division
Everglades Restoration Resource Area
South Florida Water Management District
Phones:  DESK: 561 / 681 - 2563 x3730
            CELL:  561 / 719 - 8157

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