HI, May be this helps.
dat1<-read.table(text=" TDate TTime O3 No2 Temp Sun Wspeed Wdirect Hum Indicator 1 19980101 2400 0.065 0.036 31.4 765 9.9 351 NA 1 2 19980102 2400 0.053 0.025 31.8 624 7.7 351 NA 1 3 19980103 2400 0.027 0.033 31.5 852 8.8 331 NA 2 4 19980104 2400 0.034 0.023 30.7 679 7.0 338 NA 2 5 19980105 2400 0.019 0.016 28.1 376 9.6 354 NA 1 6 19980106 2400 0.021 0.018 29.9 603 9.3 356 NA 1 7 19980107 2400 0.026 0.047 31.2 857 10.7 336 NA 1 8 19980108 2400 0.024 0.014 31.1 635 7.8 330 NA 1 9 19980109 2400 0.058 0.033 32.5 742 10.7 334 NA 1 10 19980110 2400 0.026 0.032 33.9 923 10.6 347 NA 2 11 19980111 2400 0.064 0.034 32.5 751 6.3 355 NA 2 12 19980112 2400 0.066 0.034 33.3 697 8.5 319 NA 1 13 19980113 2400 0.026 0.030 33.4 992 12.5 341 NA 1 14 19980114 2400 0.101 0.028 33.8 705 8.7 349 NA 1 15 19980115 2400 0.069 0.030 33.3 718 11.4 348 NA 1 16 19980116 2400 0.054 0.026 33.4 639 10.9 354 NA 1 17 19980117 2400 0.090 0.039 33.1 653 13.2 342 NA 2 18 19980118 2400 0.048 0.017 33.2 825 10.8 323 NA 2 19 19980119 2400 0.038 0.027 33.7 984 10.3 353 NA 1 20 19980120 2400 0.026 0.032 34.2 994 15.0 357 NA 1 21 19980121 2400 0.065 0.044 33.8 999 17.5 343 NA 1 22 19980122 2400 0.046 0.024 33.5 931 10.1 332 NA 1 23 19980123 2400 0.050 0.041 33.9 881 11.3 353 NA 1 24 19980124 2400 0.036 0.027 33.8 877 9.1 328 NA 2 25 19980125 2400 0.043 0.021 33.2 777 10.5 340 NA 2 26 19980126 2400 0.029 0.016 33.1 999 14.1 341 NA 1 27 19980127 2400 0.033 0.030 33.9 943 12.9 344 NA 1 28 19980128 2400 0.040 0.022 33.7 805 12.6 354 NA 1 29 19980129 2400 0.029 0.015 30.2 512 7.4 356 NA 1 30 19980130 2400 0.027 0.013 31.7 656 13.9 349 NA 1 ",sep="",header=TRUE,stringsAsFactors=FALSE) #creating NA for 10% of data in the specified columns (deviant of David's method). is.na(dat1[sample(1:nrow(dat1),0.1*nrow(dat1)),3:7])<-TRUE tail(dat1) # TDate TTime O3 No2 Temp Sun Wspeed Wdirect Hum Indicator #25 19980125 2400 NA NA NA NA NA 340 NA 2 #26 19980126 2400 0.029 0.016 33.1 999 14.1 341 NA 1 #27 19980127 2400 0.033 0.030 33.9 943 12.9 344 NA 1 #28 19980128 2400 0.040 0.022 33.7 805 12.6 354 NA 1 #29 19980129 2400 0.029 0.015 30.2 512 7.4 356 NA 1 #30 19980130 2400 0.027 0.013 31.7 656 13.9 349 NA 1 #If you need to create NA for individual columns randomly res<-do.call(cbind,lapply(lapply(dat1[,3:7],function(x) data.frame(x)),function(x) x[sample(1:nrow(x),0.1*nrow(x)),])) dat1[,3][dat1[,3]%in%res[,1]]<-NA dat1[,4][dat1[,4]%in%res[,2]]<-NA dat1[,5][dat1[,5]%in%res[,3]]<-NA dat1[,6][dat1[,6]%in%res[,4]]<-NA dat1[,7][dat1[,7]%in%res[,5]]<-NA head(dat1) # TDate TTime O3 No2 Temp Sun Wspeed Wdirect Hum Indicator #1 19980101 2400 0.065 0.036 31.4 765 9.9 351 NA 1 #2 19980102 2400 0.053 0.025 31.8 624 7.7 351 NA 1 #3 19980103 2400 0.027 0.033 31.5 852 8.8 331 NA 2 #4 19980104 2400 NA NA 30.7 679 7.0 338 NA 2 #5 19980105 2400 0.019 0.016 28.1 376 9.6 354 NA 1 #6 19980106 2400 0.021 0.018 29.9 603 NA 356 NA 1 A.K. ----- Original Message ----- From: Eugenie <leemean...@hotmail.com> To: r-help@r-project.org Cc: Sent: Wednesday, October 31, 2012 8:42 AM Subject: Re: [R] HELP!! how to remove 10% of data randomly in R tDate tTime O3 No2 Temp Sun Wspeed Wdirect Hum Indicator 1 19980101 2400 0.065 0.036 31.4 765 9.9 351 NA 1 2 19980102 2400 0.053 0.025 31.8 624 7.7 351 NA 1 3 19980103 2400 0.027 0.033 31.5 852 8.8 331 NA 2 4 19980104 2400 0.034 0.023 30.7 679 7.0 338 NA 2 5 19980105 2400 0.019 0.016 28.1 376 9.6 354 NA 1 6 19980106 2400 0.021 0.018 29.9 603 9.3 356 NA 1 7 19980107 2400 0.026 0.047 31.2 857 10.7 336 NA 1 8 19980108 2400 0.024 0.014 31.1 635 7.8 330 NA 1 9 19980109 2400 0.058 0.033 32.5 742 10.7 334 NA 1 10 19980110 2400 0.026 0.032 33.9 923 10.6 347 NA 2 11 19980111 2400 0.064 0.034 32.5 751 6.3 355 NA 2 12 19980112 2400 0.066 0.034 33.3 697 8.5 319 NA 1 13 19980113 2400 0.026 0.030 33.4 992 12.5 341 NA 1 14 19980114 2400 0.101 0.028 33.8 705 8.7 349 NA 1 15 19980115 2400 0.069 0.030 33.3 718 11.4 348 NA 1 16 19980116 2400 0.054 0.026 33.4 639 10.9 354 NA 1 17 19980117 2400 0.090 0.039 33.1 653 13.2 342 NA 2 18 19980118 2400 0.048 0.017 33.2 825 10.8 323 NA 2 19 19980119 2400 0.038 0.027 33.7 984 10.3 353 NA 1 20 19980120 2400 0.026 0.032 34.2 994 15.0 357 NA 1 21 19980121 2400 0.065 0.044 33.8 999 17.5 343 NA 1 22 19980122 2400 0.046 0.024 33.5 931 10.1 332 NA 1 23 19980123 2400 0.050 0.041 33.9 881 11.3 353 NA 1 24 19980124 2400 0.036 0.027 33.8 877 9.1 328 NA 2 25 19980125 2400 0.043 0.021 33.2 777 10.5 340 NA 2 26 19980126 2400 0.029 0.016 33.1 999 14.1 341 NA 1 27 19980127 2400 0.033 0.030 33.9 943 12.9 344 NA 1 28 19980128 2400 0.040 0.022 33.7 805 12.6 354 NA 1 29 19980129 2400 0.029 0.015 30.2 512 7.4 356 NA 1 30 19980130 2400 0.027 0.013 31.7 656 13.9 349 NA 1 if given data like this,how to remove the data in O3,NO2,sun,temp,wspeed randomly??(missing values in these rows & columns) -- View this message in context: http://r.789695.n4.nabble.com/HELP-how-to-remove-10-of-data-randomly-in-R-tp4647879p4647994.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list 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. ______________________________________________ R-help@r-project.org mailing list 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.
