Introduction to Repeating Things in R: Looping by Index

Поделиться
HTML-код
  • Опубликовано: 11 сен 2024

Комментарии • 16

  • @fernanda.vallejos
    @fernanda.vallejos 4 месяца назад

    Excellent explanation!

  • @koterm
    @koterm 3 года назад +1

    Thank you Ethan for this very clear explanation!

    • @weecology
      @weecology  3 года назад +1

      Your welcome! Glad it was useful.

  • @AnkeetKumar
    @AnkeetKumar Год назад

    Amazing video...

  • @asadkhanbb
    @asadkhanbb Год назад

    Thank you

  • @larissacury7714
    @larissacury7714 2 года назад

    Thank you VERY much!

  • @marcomora4
    @marcomora4 7 месяцев назад

    How can I create a data frame on each "i" itereation. For instance if I want to remove same column on each data frame, named data 01, data02, data03, etc etc. Or maybe for this task i-loop is not the best option?, Tank you in advande!

  • @ahsanullahkhan5873
    @ahsanullahkhan5873 2 года назад

    Hi Sir , really well explained .
    I have a query ,So my input files are in .nc format and its name starts with "pr" so its easy to list/choose them with list.files(pattern="pr") . Station file is one constant file . Now what I want is a separate output file in a .csv format for each of my input file and the name of my output file preferably would be same as that of input files. The following script does the job well if i go with one input at a time, i wanna loop it T*T . I am Noob af at programming, started learning it recently as i need it . Hoping for a reply . Thank you so much .
    CODE :
    setwd("D:\\data\\pr")
    library (raster) ## load required library
    library(sp) ## load library
    library(ncdf4)
    station.data = read.csv("stations.csv", sep = ",", header =T) ## import station data.file
    lon.lat = station.data[,c(2,3)] ## extract data of all stations in station file for which point values are to be extractd
    lon.lat = SpatialPoints(lon.lat) ## lon.lat for further use
    lon.lat
    robject = brick(inputfile, varname = "pr")## import raster netcdf file from which point values are to be extractd
    dim(robject) ## check the dimensions of project
    vall = extract(robject , lon.lat, method = "simple" ) ## extract values
    vall = t(vall)
    write.csv(vall, file = "output_file.csv", fileEncoding = "macroman") } ## save output csv file containing extracted point values .

    • @weecology
      @weecology  2 года назад +1

      Glad it's useful! Start by taking a look at our video on looping over files to understand the basics: ruclips.net/video/4-uWgh5kDSc/видео.html
      In your case you want something like:
      data_files = list.files(pattern="pr")
      for (current_file in data_files) {
      station.data = read.csv(current_file, sep = ",", header = T)
      # The rest of your code
      write.csv(vall, file = paste("output_", current_file), fileEncoding = "macroman")
      }
      The paste() in the last line means that the output file will be named "output_" plus the name of the input file. If you just used current_file instead it would overwrite your input file.

    • @ahsanullahkhan5873
      @ahsanullahkhan5873 2 года назад

      @@weecology thank you so much , its working like magicccc

  • @user-hp9bx2dk3v
    @user-hp9bx2dk3v Год назад

    Hello sir if i plus a mass to the right hand of the equation .and give a initial value of mass.
    Your method do not work . Can you help me?

    • @weecology
      @weecology  Год назад

      Can you include the code here to help me understand what you're trying to do?