Databases
StackOverflow2013
Postsdbo
POHow to assign start times of observations to blocks of hours in R
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POHow to assign start times of observations to blocks of hours in R
    primarykey
    data
    text
    <p>I have this df where I have columns with date&amp;time, date, and time. And of course the observations of CH4 and the calculated Ratio (I have more, but that is unrelevant to this question).</p> <pre><code>'data.frame': 1420847 obs. of 17 variables $ Start : Factor w/ 1469 levels "2013-08-31 23:56:09.000",..: 2 2 2 2 2 2 2 2 2 2 ... $ CO2 : int 1510 1950 1190 1170 780 870 730 740 680 700 ... $ CH4 : int 66 77 62 58 34 51 36 43 32 40 ... $ Ratio : num 0.0437 0.0395 0.0521 0.0496 0.0436 ... $ Start_time: POSIXlt, format: "2013-11-20 00:10:05" "2013-11-20 00:10:05" "2013-11-20 00:10:05" "2013-11-20 00:10:05" ... $ Start_date: Date, format: "2013-09-01" "2013-09-01" "2013-09-01" "2013-09-01" ... </code></pre> <p>Now I wish to split every day in six blocks of 4 hrs and to assign numbers 1 - 6 to each block. The problem, however, is that I only have the date and time at which the measurements started (<code>Start_date</code> and <code>Start_time</code>, or the combined <code>Start</code>), so I think it is necessary to assign each new <code>Start_time</code> to a <code>block</code>. The length of the observations varies a lot, so there is no option of assigning a number to it. This is what I wish to accomplish:</p> <pre><code> Start Start_time Start_date CO2 CH4 Ratio block 2013-09-01 00:10:05.000 00:10:05 2013-09-01 1510 66 0.04370861 1 2013-09-01 00:10:05.000 00:10:05 2013-09-01 1950 77 0.03948718 1 2013-09-01 05:16:55.000 05:16:55 2013-09-01 1190 62 0.05210084 2 2013-09-01 05:16:55.000 05:16:55 2013-09-01 1170 58 0.04957265 2 2013-09-01 05:16:55.000 05:16:55 2013-09-01 780 34 0.04358974 2 2013-09-01 12:44:33.000 12:44:33 2013-09-01 870 51 0.05862069 4 2013-09-01 12:44:33.000 12:44:33 2013-09-01 730 36 0.04931507 4 2013-09-01 22:14:23.000 22:14:23 2013-09-01 740 43 0.05810811 6 2013-09-01 22:14:23.000 22:14:23 2013-09-01 680 32 0.04705882 6 2013-09-02 08:37:05.000 08:37:05 2013-09-02 700 40 0.05714286 3 2013-09-02 08:37:05.000 08:37:05 2013-09-02 610 35 0.05737705 3 2013-09-02 17:22:33.000 17:22:33 2013-09-02 630 25 0.03968254 5 2013-09-02 17:22:33.000 17:22:33 2013-09-02 670 40 0.05970149 5 2013-09-02 23:59:44.000 23:59:44 2013-09-02 640 37 0.05781250 6 2013-09-02 23:59:44.000 23:59:44 2013-09-02 730 35 0.04794521 6 </code></pre> <p>I have searched this website and also tried Google but, so far, I have found no answer. I have tried the following code, which I found in an answer on this website but no luck.</p> <pre><code>qaa &lt;- split(df, cut(strptime(paste(df$Start_date, df$Start_time), format = "%Y-%m-%d %H:%M"),"4 hours")) </code></pre> <p>Previously, I tried to split the number of observations in minutes, so I tried to adjust that code. And to be very honest, I have no idea what I am doing (as you can probably tell).</p> <pre><code>lst&lt;- split(df, df$Start_date) nobs &lt;- "4 hours" List &lt;- unlist(lapply(lst, function(x) { x$grp &lt;- rep(1:(nrow(x)/nobs+1), each = nobs)[1:nrow(x)] split(x, x$grp)}), recursive = FALSE) b &lt;- as.matrix(do.call("rbind", List)) </code></pre> <p>Just to let you know, again, I am a NOOB concerning R so it takes me a lot of time to figure everything out. I understand very little of the language but I am trying my very best to make it work. I really enjoy working with it! If there is already another question like this on this website, please let me know so I can remove this.. I have not found it, though.</p> <p>Thank you for taking your time to read my question and to consider to answer it!</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USJalalala
    plurals
    1. PL
      singulars
      1. LTLinked
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POHow to assign start times of observations to blocks of hours in R
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload