Cristina Silva
2017-Jul-11 13:25 UTC
[R] Problems with time formats when importing data using readHTMLTable
Dear Jeff,
I am sorry, I didn't notice that it was not plain text. I hope that it
is now in the correct format. I explain the problem again, now with more
detais.
I am collecting the track positions of our research vessel from
www.marinetraffic.com. In the page, the data appear in a table:
Timestamp Source Speed (kn) Latitude (?) Longitude (?)
Course (?) Show on Map
2017-07-11 10:57 (UTC) Terr-AIS 8.6 37.36228 -9.176811 200
2017-07-11 10:54 (UTC) Terr-AIS 8.4 37.36875 -9.174048 200
2017-07-11 09:50 (UTC) Terr-AIS 8 37.51499 -9.184502 149
2017-07-11 09:08 (UTC) Terr-AIS 7.7 37.60513 -9.228263 169
2017-07-11 09:05 (UTC) Terr-AIS 8 37.61168 -9.229627 167
2017-07-11 09:03 (UTC) Terr-AIS 6.9 37.61626 -9.230456 132
2017-07-11 08:59 (UTC) Terr-AIS 3.4 37.61758 -9.237928 101
2017-07-11 08:57 (UTC) Terr-AIS 3.6 37.61808 -9.240235 116
2017-07-11 08:47 (UTC) Terr-AIS 3.3 37.62267 -9.249762 112
2017-07-11 08:44 (UTC) Terr-AIS 3.2 37.6241 -9.25348 115
2017-07-11 08:40 (UTC) Terr-AIS 3.3 37.62557 -9.257295 112
2017-07-11 08:32 (UTC) Terr-AIS 3.4 37.62903 -9.266028 111
2017-07-11 08:28 (UTC) Terr-AIS 3.3 37.63051 -9.269725 114
2017-07-11 08:25 (UTC) Terr-AIS 3.3 37.63207 -9.273642 120
2017-07-11 08:20 (UTC) Terr-AIS 3.6 37.63395 -9.278254 118
2017-07-11 08:16 (UTC) Terr-AIS 3.3 37.63586 -9.282853 116
2017-07-11 08:08 (UTC) Terr-AIS 3.2 37.6392 -9.291157 118
2017-07-11 07:38 (UTC) Sat-AIS
2017-07-11 06:58 (UTC) Terr-AIS 3 37.68459 -9.321658 159
2017-07-11 06:53 (UTC) Terr-AIS 3.3 37.68881 -9.324172 150
To get this table I had to copy manually from the webpage, paste in a
text file, delete information on figures, links, etc. and then import to
R. This works well, I read the csv file and have no problems with date
formats. But instead of 20 records, I have to import e.g. 500 records,
i.e. 10 pages of 50 records each, or more. I want to import these data
in a more automated and quick procedure. I have done this before with no
problems, but probably the webpage changed some permissions.
Here is the script used to get the data directly from the webpage into
R, for a sample of 20 records (10 per page):
library(XML)
x <- list()
for (i in 1:2)
{
x[i]<-
readHTMLTable(paste('http://www.marinetraffic.com/en/ais/index/positions/all/shipid:318358/mmsi:263601000/shipname:NORUEGA/per_page:10/page:',
i, sep=''))
}
ais <- do.call('rbind', x)
ais <- ais[,-7]
and I got the following table:
> ais
Timestamp Source
Speed (kn) Latitude (??) Longitude (??) Course (??)
1 149977066014997706604 minutes ago Terr-AIS
8.6 37.36228 -9.176811 200
2 149977048714997704876 minutes ago Terr-AIS
8.4 37.36875 -9.174048 200
3 149976661414997666141 hour, 11 minutes ago Terr-AIS
8.0 37.51499 -9.184502 149
4 149976410714997641071 hour, 53 minutes ago Terr-AIS
7.7 37.60513 -9.228263 169
5 149976392714997639271 hour, 56 minutes ago Terr-AIS
8.0 37.61168 -9.229627 167
6 149976378014997637801 hour, 58 minutes ago Terr-AIS
6.9 37.61626 -9.230456 132
7 149976354014997635402 hours, 2 minutes ago Terr-AIS
3.4 37.61758 -9.237928 101
8 149976342014997634202 hours, 4 minutes ago Terr-AIS
3.6 37.61808 -9.240235 116
9 149976286114997628612 hours, 14 minutes ago Terr-AIS
3.3 37.62267 -9.249762 112
10 149976264714997626472 hours, 17 minutes ago Terr-AIS
3.2 37.6241 -9.25348 115
11 149976243014997624302 hours, 21 minutes ago Terr-AIS
3.3 37.62557 -9.257295 112
12 149976193714997619372 hours, 29 minutes ago Terr-AIS
3.4 37.62903 -9.266028 111
13 149976172814997617282 hours, 32 minutes ago Terr-AIS
3.3 37.63051 -9.269725 114
14 149976150714997615072 hours, 36 minutes ago Terr-AIS
3.3 37.63207 -9.273642 120
15 149976124714997612472 hours, 40 minutes ago Terr-AIS
3.6 37.63395 -9.278254 118
16 149976098714997609872 hours, 45 minutes ago Terr-AIS
3.3 37.63586 -9.282853 116
17 149976051014997605102 hours, 53 minutes ago Terr-AIS
3.2 37.6392 -9.291157 118
18 149975870414997587043 hours, 23 minutes ago Sat-AIS Add to SAT
Fleet for undelayed data <NA> <NA> <NA>
19 149975631414997563144 hours, 3 minutes ago Terr-AIS
3.0 37.68459 -9.321658 159
20 149975598814997559884 hours, 8 minutes ago Terr-AIS
3.3 37.68881 -9.324172 150
The records correspond exactly to the first table. I have tried to
change the colClasses to character, but the results are always the same.
My question is: how to change the Timestamp to a POSIXlt POSIXct format,
either in the importing phase or within R?
I hope that the question is clear now.
Cristina
On Mon, 10 Jul 2017 09:18:05 -0700, Jeff Newmiller
wrote:> Not reproducible. [1][2][3] If our answers don't seem to apply to
> your situation, it will likely be because you did not explain your
> question clearly.
>
> Not plain text. This is a plain text mailing list, and the best-case
> scenario when you let your email program send HTML is that what you
> saw is not what we see (worst case is your email is scrambled on our
> end).
>
> Have you read the documentation for the function you are using? In
> particular, what about the colClasses argument? If you don't let
> readHTMLTable guess what the format is (have it read in as character
> data) then you have a fighting chance to get it right yourself, e.g.
>
> as.POSIXct( "2017-07-10 14:04 (UTC)", format="%Y-%m-%d %H:%M
(UTC)",
> tz="UTC" )
>
> -----
>
> [1]
>
>
http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example
>
> [2] http://adv-r.had.co.nz/Reproducibility.html
>
> [3] https://cran.r-project.org/web/packages/reprex/index.html
> --
> Sent from my phone. Please excuse my brevity.
>
> On July 10, 2017 8:31:30 AM PDT, Cristina Silva <csilva at ipma.pt>
> wrote:
>>Hi,
>>
>>I am extracting positions data from the marine traffic website. The
>>table has a "Timestamp" column which, in the browser, appears
with
>> the
>>format yyyy-mm-dd HH:MM (UTC), e.g. 2017-07-10 14:04 (UTC).
>>
>>When I import the table, the same date "2017-07-10 14:04
(UTC)"
>> appears
>>
>>as "1499696500149969650021 minutes ago", This is the more
recent date
>>and time. Older records, as e.g. "2017-07-09 17:02 (UTC)"
appear as
>>e.g.
>>"1499619726149961972621 hours, 59 minutes ago".
>>
>>I don't know how to convert these data to the time formats used in R
>>(POSIXct).
>>
>>The script is very simple and worked before:
>>
>>library(XML)
>>x <- readHTMLTable('url')
>>
>>where the 'url' is the link to the website with the
specification of
>>the
>>vessel.
>>
>>I appreciate any help.
>>
>>Cristina
>>
>>--
>>Cristina Silva
>>Divis?o de Modela??o e Gest?o de Recursos Pesqueiros
>>Av. Dr. Alfredo Magalh?es Ramalho
>>1495-165 Lisboa
>>@: csilva at ipma.pt <mailto:csilva at ipma.pt>
>>#: +351 213027096 <phoneto:+351213027096>
>>
>>
>> [[alternative HTML version deleted]]
>>
>>______________________________________________
>>R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
>>https://stat.ethz.ch/mailman/listinfo/r-help
>>PLEASE do read the posting guide
>>http://www.R-project.org/posting-guide.html
>>and provide commented, minimal, self-contained, reproducible code.
--
Cristina Silva
Divis?o de Modela??o e Gest?o de Recursos Pesqueiros
Avenida de Bras?lia
1449-006 Lisboa
@: csilva at ipma.pt
#: +351 213027096
David Winsemius
2017-Jul-11 14:15 UTC
[R] Problems with time formats when importing data using readHTMLTable
> On Jul 11, 2017, at 6:25 AM, Cristina Silva <csilva at ipma.pt> wrote: > > Dear Jeff, > > I am sorry, I didn't notice that it was not plain text. I hope that it is now in the correct format. I explain the problem again, now with more detais. > I am collecting the track positions of our research vessel from www.marinetraffic.com. In the page, the data appear in a table: > > Timestamp Source Speed (kn) Latitude (?) Longitude (?) Course (?) Show on Map > 2017-07-11 10:57 (UTC) Terr-AIS 8.6 37.36228 -9.176811 200 > 2017-07-11 10:54 (UTC) Terr-AIS 8.4 37.36875 -9.174048 200 > 2017-07-11 09:50 (UTC) Terr-AIS 8 37.51499 -9.184502 149 > 2017-07-11 09:08 (UTC) Terr-AIS 7.7 37.60513 -9.228263 169 > 2017-07-11 09:05 (UTC) Terr-AIS 8 37.61168 -9.229627 167 > 2017-07-11 09:03 (UTC) Terr-AIS 6.9 37.61626 -9.230456 132 > 2017-07-11 08:59 (UTC) Terr-AIS 3.4 37.61758 -9.237928 101 > 2017-07-11 08:57 (UTC) Terr-AIS 3.6 37.61808 -9.240235 116 > 2017-07-11 08:47 (UTC) Terr-AIS 3.3 37.62267 -9.249762 112 > 2017-07-11 08:44 (UTC) Terr-AIS 3.2 37.6241 -9.25348 115 > 2017-07-11 08:40 (UTC) Terr-AIS 3.3 37.62557 -9.257295 112 > 2017-07-11 08:32 (UTC) Terr-AIS 3.4 37.62903 -9.266028 111 > 2017-07-11 08:28 (UTC) Terr-AIS 3.3 37.63051 -9.269725 114 > 2017-07-11 08:25 (UTC) Terr-AIS 3.3 37.63207 -9.273642 120 > 2017-07-11 08:20 (UTC) Terr-AIS 3.6 37.63395 -9.278254 118 > 2017-07-11 08:16 (UTC) Terr-AIS 3.3 37.63586 -9.282853 116 > 2017-07-11 08:08 (UTC) Terr-AIS 3.2 37.6392 -9.291157 118 > 2017-07-11 07:38 (UTC) Sat-AIS > 2017-07-11 06:58 (UTC) Terr-AIS 3 37.68459 -9.321658 159 > 2017-07-11 06:53 (UTC) Terr-AIS 3.3 37.68881 -9.324172 150 > > To get this table I had to copy manually from the webpage, paste in a text file, delete information on figures, links, etc. and then import to R. This works well, I read the csv file and have no problems with date formats. But instead of 20 records, I have to import e.g. 500 records, i.e. 10 pages of 50 records each, or more. I want to import these data in a more automated and quick procedure. I have done this before with no problems, but probably the webpage changed some permissions. > > Here is the script used to get the data directly from the webpage into R, for a sample of 20 records (10 per page): > > library(XML) > x <- list() > for (i in 1:2) > { > x[i]<- readHTMLTable(paste('http://www.marinetraffic.com/en/ais/index/positions/all/shipid:318358/mmsi:263601000/shipname:NORUEGA/per_page:10/page:', i, sep='')) > } > > ais <- do.call('rbind', x) > ais <- ais[,-7] > > and I got the following table: > >> ais > Timestamp Source Speed (kn) Latitude (??) Longitude (??) Course (??) > 1 149977066014997706604 minutes ago Terr-AIS 8.6 37.36228 -9.176811 200There's undoubtedly a way to extract the time info from this HTML code (but I'm not the one to provide that solution.) This is the first entry in the webpage source when viewed right now: <td> <time class="toggle_time utc_time hide-me formatTime" data-overrideAbbreviation="empty" data-time="1499780737" data-timezone="0"><span>1499780737</span></time><time class="toggle_time my_time hide-me formatTime" data-overrideAbbreviation="MyT" data-time="1499780737" data-timezone="MyT"><span>1499780737</span></time><time class="toggle_time dif_time hide"><span>6 minutes ago</span></time> </td> So the POSIX-style time is givne twice (with no separator and then an offset in minutes is calculated. If I were given the records as you have them now I would extract the leading 10 digits and convert to POSIXct as.POSIXct(as.numeric(gsub("(^.{10}).+","", Timestamp)), origin="1970-01-01") as.POSIXct(as.numeric(gsub("(^.{10}).+","\\1", ais$Timestamp)), origin="1970-01-01") [1] "2017-07-11 07:09:57 PDT" "2017-07-11 06:45:37 PDT" "2017-07-11 06:40:34 PDT" "2017-07-11 06:34:46 PDT" "2017-07-11 06:32:26 PDT" [6] "2017-07-11 06:29:34 PDT" "2017-07-11 06:26:37 PDT" "2017-07-11 06:20:24 PDT" "2017-07-11 06:17:18 PDT" "2017-07-11 06:12:37 PDT" [11] "2017-07-11 06:08:24 PDT" "2017-07-11 06:05:04 PDT" "2017-07-11 06:03:27 PDT" "2017-07-11 05:59:37 PDT" "2017-07-11 05:54:37 PDT" [16] "2017-07-11 05:50:48 PDT" "2017-07-11 05:44:53 PDT" "2017-07-11 05:29:17 PDT" "2017-07-11 05:26:44 PDT" "2017-07-11 04:30:08 PDT" -- David.> 2 149977048714997704876 minutes ago Terr-AIS 8.4 37.36875 -9.174048 200 > 3 149976661414997666141 hour, 11 minutes ago Terr-AIS 8.0 37.51499 -9.184502 149 > 4 149976410714997641071 hour, 53 minutes ago Terr-AIS 7.7 37.60513 -9.228263 169 > 5 149976392714997639271 hour, 56 minutes ago Terr-AIS 8.0 37.61168 -9.229627 167 > 6 149976378014997637801 hour, 58 minutes ago Terr-AIS 6.9 37.61626 -9.230456 132 > 7 149976354014997635402 hours, 2 minutes ago Terr-AIS 3.4 37.61758 -9.237928 101 > 8 149976342014997634202 hours, 4 minutes ago Terr-AIS 3.6 37.61808 -9.240235 116 > 9 149976286114997628612 hours, 14 minutes ago Terr-AIS 3.3 37.62267 -9.249762 112 > 10 149976264714997626472 hours, 17 minutes ago Terr-AIS 3.2 37.6241 -9.25348 115 > 11 149976243014997624302 hours, 21 minutes ago Terr-AIS 3.3 37.62557 -9.257295 112 > 12 149976193714997619372 hours, 29 minutes ago Terr-AIS 3.4 37.62903 -9.266028 111 > 13 149976172814997617282 hours, 32 minutes ago Terr-AIS 3.3 37.63051 -9.269725 114 > 14 149976150714997615072 hours, 36 minutes ago Terr-AIS 3.3 37.63207 -9.273642 120 > 15 149976124714997612472 hours, 40 minutes ago Terr-AIS 3.6 37.63395 -9.278254 118 > 16 149976098714997609872 hours, 45 minutes ago Terr-AIS 3.3 37.63586 -9.282853 116 > 17 149976051014997605102 hours, 53 minutes ago Terr-AIS 3.2 37.6392 -9.291157 118 > 18 149975870414997587043 hours, 23 minutes ago Sat-AIS Add to SAT Fleet for undelayed data <NA> <NA> <NA> > 19 149975631414997563144 hours, 3 minutes ago Terr-AIS 3.0 37.68459 -9.321658 159 > 20 149975598814997559884 hours, 8 minutes ago Terr-AIS 3.3 37.68881 -9.324172 150 > > The records correspond exactly to the first table. I have tried to change the colClasses to character, but the results are always the same. My question is: how to change the Timestamp to a POSIXlt POSIXct format, either in the importing phase or within R? > > I hope that the question is clear now. > > Cristina > > > On Mon, 10 Jul 2017 09:18:05 -0700, Jeff Newmiller wrote: >> Not reproducible. [1][2][3] If our answers don't seem to apply to >> your situation, it will likely be because you did not explain your >> question clearly. >> >> Not plain text. This is a plain text mailing list, and the best-case >> scenario when you let your email program send HTML is that what you >> saw is not what we see (worst case is your email is scrambled on our >> end). >> >> Have you read the documentation for the function you are using? In >> particular, what about the colClasses argument? If you don't let >> readHTMLTable guess what the format is (have it read in as character >> data) then you have a fighting chance to get it right yourself, e.g. >> >> as.POSIXct( "2017-07-10 14:04 (UTC)", format="%Y-%m-%d %H:%M (UTC)", >> tz="UTC" ) >> >> ----- >> >> [1] >> http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example >> >> [2] http://adv-r.had.co.nz/Reproducibility.html >> >> [3] https://cran.r-project.org/web/packages/reprex/index.html >> -- >> Sent from my phone. Please excuse my brevity. >> >> On July 10, 2017 8:31:30 AM PDT, Cristina Silva <csilva at ipma.pt> wrote: >>> Hi, >>> >>> I am extracting positions data from the marine traffic website. The >>> table has a "Timestamp" column which, in the browser, appears with the >>> format yyyy-mm-dd HH:MM (UTC), e.g. 2017-07-10 14:04 (UTC). >>> >>> When I import the table, the same date "2017-07-10 14:04 (UTC)" appears >>> >>> as "1499696500149969650021 minutes ago", This is the more recent date >>> and time. Older records, as e.g. "2017-07-09 17:02 (UTC)" appear as >>> e.g. >>> "1499619726149961972621 hours, 59 minutes ago". >>> >>> I don't know how to convert these data to the time formats used in R >>> (POSIXct). >>> >>> The script is very simple and worked before: >>> >>> library(XML) >>> x <- readHTMLTable('url') >>> >>> where the 'url' is the link to the website with the specification of >>> the >>> vessel. >>> >>> I appreciate any help. >>> >>> Cristina >>> >>> -- >>> Cristina Silva >>> Divis?o de Modela??o e Gest?o de Recursos Pesqueiros >>> Av. Dr. Alfredo Magalh?es Ramalho >>> 1495-165 Lisboa >>> @: csilva at ipma.pt <mailto:csilva at ipma.pt> >>> #: +351 213027096 <phoneto:+351213027096> >>> >>> >>> [[alternative HTML version deleted]] >>> >>> ______________________________________________ >>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >>> https://stat.ethz.ch/mailman/listinfo/r-help >>> PLEASE do read the posting guide >>> http://www.R-project.org/posting-guide.html >>> and provide commented, minimal, self-contained, reproducible code. > > -- > Cristina Silva > Divis?o de Modela??o e Gest?o de Recursos Pesqueiros > Avenida de Bras?lia > 1449-006 Lisboa > @: csilva at ipma.pt > #: +351 213027096 > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.David Winsemius Alameda, CA, USA
Cristina Silva
2017-Jul-11 17:00 UTC
[R] Problems with time formats when importing data using readHTMLTable
Dear David, Thank you very much. You have solved my problem, not of importing in the right format but the date conversion. It works for me, and if I specify the timezone tz='GMT', I get exactly the same time of the webpage. Sincerely yours, Cristina On Tue, 11 Jul 2017 07:15:43 -0700, David Winsemius wrote:>> On Jul 11, 2017, at 6:25 AM, Cristina Silva <csilva at ipma.pt> wrote: >> >> Dear Jeff, >> >> I am sorry, I didn't notice that it was not plain text. I hope that >> it is now in the correct format. I explain the problem again, now with >> more detais. >> I am collecting the track positions of our research vessel from >> www.marinetraffic.com. In the page, the data appear in a table: >> >> Timestamp Source Speed (kn) Latitude (?) Longitude (?) >> Course (?) Show on Map >> 2017-07-11 10:57 (UTC) Terr-AIS 8.6 37.36228 -9.176811 >> 200 >> 2017-07-11 10:54 (UTC) Terr-AIS 8.4 37.36875 -9.174048 >> 200 >> 2017-07-11 09:50 (UTC) Terr-AIS 8 37.51499 -9.184502 >> 149 >> 2017-07-11 09:08 (UTC) Terr-AIS 7.7 37.60513 -9.228263 >> 169 >> 2017-07-11 09:05 (UTC) Terr-AIS 8 37.61168 -9.229627 >> 167 >> 2017-07-11 09:03 (UTC) Terr-AIS 6.9 37.61626 -9.230456 >> 132 >> 2017-07-11 08:59 (UTC) Terr-AIS 3.4 37.61758 -9.237928 >> 101 >> 2017-07-11 08:57 (UTC) Terr-AIS 3.6 37.61808 -9.240235 >> 116 >> 2017-07-11 08:47 (UTC) Terr-AIS 3.3 37.62267 -9.249762 >> 112 >> 2017-07-11 08:44 (UTC) Terr-AIS 3.2 37.6241 -9.25348 >> 115 >> 2017-07-11 08:40 (UTC) Terr-AIS 3.3 37.62557 -9.257295 >> 112 >> 2017-07-11 08:32 (UTC) Terr-AIS 3.4 37.62903 -9.266028 >> 111 >> 2017-07-11 08:28 (UTC) Terr-AIS 3.3 37.63051 -9.269725 >> 114 >> 2017-07-11 08:25 (UTC) Terr-AIS 3.3 37.63207 -9.273642 >> 120 >> 2017-07-11 08:20 (UTC) Terr-AIS 3.6 37.63395 -9.278254 >> 118 >> 2017-07-11 08:16 (UTC) Terr-AIS 3.3 37.63586 -9.282853 >> 116 >> 2017-07-11 08:08 (UTC) Terr-AIS 3.2 37.6392 -9.291157 >> 118 >> 2017-07-11 07:38 (UTC) Sat-AIS >> 2017-07-11 06:58 (UTC) Terr-AIS 3 37.68459 -9.321658 >> 159 >> 2017-07-11 06:53 (UTC) Terr-AIS 3.3 37.68881 -9.324172 >> 150 >> >> To get this table I had to copy manually from the webpage, paste in >> a text file, delete information on figures, links, etc. and then >> import to R. This works well, I read the csv file and have no problems >> with date formats. But instead of 20 records, I have to import e.g. >> 500 records, i.e. 10 pages of 50 records each, or more. I want to >> import these data in a more automated and quick procedure. I have done >> this before with no problems, but probably the webpage changed some >> permissions. >> >> Here is the script used to get the data directly from the webpage >> into R, for a sample of 20 records (10 per page): >> >> library(XML) >> x <- list() >> for (i in 1:2) >> { >> x[i]<- >> readHTMLTable(paste('http://www.marinetraffic.com/en/ais/index/positions/all/shipid:318358/mmsi:263601000/shipname:NORUEGA/per_page:10/page:', >> i, sep='')) >> } >> >> ais <- do.call('rbind', x) >> ais <- ais[,-7] >> >> and I got the following table: >> >>> ais >> Timestamp Source >> Speed (kn) Latitude (??) Longitude (??) Course (??) >> 1 149977066014997706604 minutes ago Terr-AIS >> 8.6 37.36228 -9.176811 200 > > There's undoubtedly a way to extract the time info from this HTML > code (but I'm not the one to provide that solution.) This is the > first > entry in the webpage source when viewed right now: > > <td> > <time class="toggle_time utc_time hide-me formatTime" > data-overrideAbbreviation="empty" data-time="1499780737" > data-timezone="0"><span>1499780737</span></time><time > class="toggle_time my_time hide-me formatTime" > data-overrideAbbreviation="MyT" data-time="1499780737" > data-timezone="MyT"><span>1499780737</span></time><time > class="toggle_time dif_time hide"><span>6 minutes > ago</span></time> </td> > > So the POSIX-style time is givne twice (with no separator and then an > offset in minutes is calculated. If I were given the records as you > have them now I would extract the leading 10 digits and convert to > POSIXct > > as.POSIXct(as.numeric(gsub("(^.{10}).+","", Timestamp)), > origin="1970-01-01") > > as.POSIXct(as.numeric(gsub("(^.{10}).+","\\1", ais$Timestamp)), > origin="1970-01-01") > [1] "2017-07-11 07:09:57 PDT" "2017-07-11 06:45:37 PDT" "2017-07-11 > 06:40:34 PDT" "2017-07-11 06:34:46 PDT" "2017-07-11 06:32:26 PDT" > [6] "2017-07-11 06:29:34 PDT" "2017-07-11 06:26:37 PDT" "2017-07-11 > 06:20:24 PDT" "2017-07-11 06:17:18 PDT" "2017-07-11 06:12:37 PDT" > [11] "2017-07-11 06:08:24 PDT" "2017-07-11 06:05:04 PDT" "2017-07-11 > 06:03:27 PDT" "2017-07-11 05:59:37 PDT" "2017-07-11 05:54:37 PDT" > [16] "2017-07-11 05:50:48 PDT" "2017-07-11 05:44:53 PDT" "2017-07-11 > 05:29:17 PDT" "2017-07-11 05:26:44 PDT" "2017-07-11 04:30:08 PDT" > > -- David. > > > >> 2 149977048714997704876 minutes ago Terr-AIS >> 8.4 37.36875 -9.174048 200 >> 3 149976661414997666141 hour, 11 minutes ago Terr-AIS >> 8.0 37.51499 -9.184502 149 >> 4 149976410714997641071 hour, 53 minutes ago Terr-AIS >> 7.7 37.60513 -9.228263 169 >> 5 149976392714997639271 hour, 56 minutes ago Terr-AIS >> 8.0 37.61168 -9.229627 167 >> 6 149976378014997637801 hour, 58 minutes ago Terr-AIS >> 6.9 37.61626 -9.230456 132 >> 7 149976354014997635402 hours, 2 minutes ago Terr-AIS >> 3.4 37.61758 -9.237928 101 >> 8 149976342014997634202 hours, 4 minutes ago Terr-AIS >> 3.6 37.61808 -9.240235 116 >> 9 149976286114997628612 hours, 14 minutes ago Terr-AIS >> 3.3 37.62267 -9.249762 112 >> 10 149976264714997626472 hours, 17 minutes ago Terr-AIS >> 3.2 37.6241 -9.25348 115 >> 11 149976243014997624302 hours, 21 minutes ago Terr-AIS >> 3.3 37.62557 -9.257295 112 >> 12 149976193714997619372 hours, 29 minutes ago Terr-AIS >> 3.4 37.62903 -9.266028 111 >> 13 149976172814997617282 hours, 32 minutes ago Terr-AIS >> 3.3 37.63051 -9.269725 114 >> 14 149976150714997615072 hours, 36 minutes ago Terr-AIS >> 3.3 37.63207 -9.273642 120 >> 15 149976124714997612472 hours, 40 minutes ago Terr-AIS >> 3.6 37.63395 -9.278254 118 >> 16 149976098714997609872 hours, 45 minutes ago Terr-AIS >> 3.3 37.63586 -9.282853 116 >> 17 149976051014997605102 hours, 53 minutes ago Terr-AIS >> 3.2 37.6392 -9.291157 118 >> 18 149975870414997587043 hours, 23 minutes ago Sat-AIS Add to SAT >> Fleet for undelayed data <NA> <NA> <NA> >> 19 149975631414997563144 hours, 3 minutes ago Terr-AIS >> 3.0 37.68459 -9.321658 159 >> 20 149975598814997559884 hours, 8 minutes ago Terr-AIS >> 3.3 37.68881 -9.324172 150 >> >> The records correspond exactly to the first table. I have tried to >> change the colClasses to character, but the results are always the >> same. My question is: how to change the Timestamp to a POSIXlt POSIXct >> format, either in the importing phase or within R? >> >> I hope that the question is clear now. >> >> Cristina >> >> >> On Mon, 10 Jul 2017 09:18:05 -0700, Jeff Newmiller wrote: >>> Not reproducible. [1][2][3] If our answers don't seem to apply to >>> your situation, it will likely be because you did not explain your >>> question clearly. >>> >>> Not plain text. This is a plain text mailing list, and the >>> best-case >>> scenario when you let your email program send HTML is that what you >>> saw is not what we see (worst case is your email is scrambled on >>> our >>> end). >>> >>> Have you read the documentation for the function you are using? In >>> particular, what about the colClasses argument? If you don't let >>> readHTMLTable guess what the format is (have it read in as >>> character >>> data) then you have a fighting chance to get it right yourself, >>> e.g. >>> >>> as.POSIXct( "2017-07-10 14:04 (UTC)", format="%Y-%m-%d %H:%M >>> (UTC)", >>> tz="UTC" ) >>> >>> ----- >>> >>> [1] >>> >>> http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example >>> >>> [2] http://adv-r.had.co.nz/Reproducibility.html >>> >>> [3] https://cran.r-project.org/web/packages/reprex/index.html >>> -- >>> Sent from my phone. Please excuse my brevity. >>> >>> On July 10, 2017 8:31:30 AM PDT, Cristina Silva <csilva at ipma.pt> >>> wrote: >>>> Hi, >>>> >>>> I am extracting positions data from the marine traffic website. >>>> The >>>> table has a "Timestamp" column which, in the browser, appears with >>>> the >>>> format yyyy-mm-dd HH:MM (UTC), e.g. 2017-07-10 14:04 (UTC). >>>> >>>> When I import the table, the same date "2017-07-10 14:04 (UTC)" >>>> appears >>>> >>>> as "1499696500149969650021 minutes ago", This is the more recent >>>> date >>>> and time. Older records, as e.g. "2017-07-09 17:02 (UTC)" appear >>>> as >>>> e.g. >>>> "1499619726149961972621 hours, 59 minutes ago". >>>> >>>> I don't know how to convert these data to the time formats used in >>>> R >>>> (POSIXct). >>>> >>>> The script is very simple and worked before: >>>> >>>> library(XML) >>>> x <- readHTMLTable('url') >>>> >>>> where the 'url' is the link to the website with the specification >>>> of >>>> the >>>> vessel. >>>> >>>> I appreciate any help. >>>> >>>> Cristina >>>>> > David Winsemius > Alameda, CA, USA-- Cristina Silva Divis?o de Modela??o e Gest?o de Recursos Pesqueiros Avenida de Bras?lia 1449-006 Lisboa @: csilva at ipma.pt #: +351 213027096
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