Dear useRs, Below is a sample of my dataset (I have more rows and columns).
As you can see in the 2nd column, there are values, the name of the parameter ('Sq' in that case), some integer ('45' in that case) and the unit ('µm' or 'nm'). I know how to extract the rows of interest (those with values), but they are expressed in different units. All values following a line with the unit are expressed in that unit, but the number of lines is not constant (sometimes each value is expressed in a different unit so there will be a new unit line, but there are sometimes several values in a row expressed in the same unit so without unit lines in between). I hope this is clear (it should be with the example provided). This messy dataset comes from an external software so I don't have any means to format the ways the data are collated. I have to find a way to deal with it in R. What I would like to do is convert the values in nm to µm; I just need to multiply by 1000. What I don't know is how to identify the values that are expressed in nm (all values that follow a line with 'nm' until there is a line with 'µm'). I don't even know how I should search online because I don't know how this kind of operation is called. Any help is appreciated. Thank you in advance. Ivan my.data <- structure(list(V1 = c("2019/05/10", "#", "#", "#", "2019/05/10", "2019/05/10", "2019/05/10", "#", "#", "#", "2019/05/10", "#", "#", "#", "2019/05/10", "#", "#", "#", "2019/05/10", "2019/05/10"), V19 = c("0.2012800083", "45", "Sq", "µm", "0.3634383236", "0.4360454777", "0.3767733568", "45", "Sq", "nm", "102.013048", "45", "Sq", "µm", "0.1413840498", "45", "Sq", "nm", "65.4459715", "46.45802917")), row.names = c(NA, 20L), class = "data.frame") -- Dr. Ivan Calandra TraCEr, laboratory for Traceology and Controlled Experiments MONREPOS Archaeological Research Centre and Museum for Human Behavioural Evolution Schloss Monrepos 56567 Neuwied, Germany +49 (0) 2631 9772-243 https://www.researchgate.net/profile/Ivan_Calandra ______________________________________________ R-help@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.