7.9 Read Strings from a File
20180604 There may be occasions where we would like to load
a dataset from a file as strings, one line as a string, returning a
vector of strings. We achieve this using the function
base::readLines(). In the following example we access the
system file weather.csv that is provided by the
rattle (G. Williams 2026) package.
library(glue) # Format strings: glue().
dsname <- "weather" # Dataset name.
ftype <- "csv" # Source dataset file type.
fname <- glue("{dsname}.{ftype}")
fname %T>%
print() %>%
system.file(ftype, ., package="rattle") %>%
readLines() ->
ds## weather.csvShow the first few lines using utils::head():
## [1] "\"Date\",\"Location\",\"MinTemp\",\"MaxTemp\",\"Rainfall\",\"Evaporation\",\"Sunshine\",\"WindGustDir\",\"WindGustSpeed\",\"WindDir9am\",\"WindDir3pm\",\"WindSpeed9am\",\"WindSpeed3pm\",\"Humidity9am\",\"Humidity3pm\",\"Pressure9am\",\"Pressure3pm\",\"Cloud9am\",\"Cloud3pm\",\"Temp9am\",\"Temp3pm\",\"RainToday\",\"RISK_MM\",\"RainTomorrow\""
## [2] "2007-11-01,\"Canberra\",8,24.3,0,3.4,6.3,\"NW\",30,\"SW\",\"NW\",6,20,68,29,1019.7,1015,7,7,14.4,23.6,\"No\",3.6,\"Yes\""
## [3] "2007-11-02,\"Canberra\",14,26.9,3.6,4.4,9.7,\"ENE\",39,\"E\",\"W\",4,17,80,36,1012.4,1008.4,5,3,17.5,25.7,\"Yes\",3.6,\"Yes\""
## [4] "2007-11-03,\"Canberra\",13.7,23.4,3.6,5.8,3.3,\"NW\",85,\"N\",\"NNE\",6,6,82,69,1009.5,1007.2,8,7,15.4,20.2,\"Yes\",39.8,\"Yes\""
## [5] "2007-11-04,\"Canberra\",13.3,15.5,39.8,7.2,9.1,\"NW\",54,\"WNW\",\"W\",30,24,62,56,1005.5,1007,2,7,13.5,14.1,\"Yes\",2.8,\"Yes\""
## [6] "2007-11-05,\"Canberra\",7.6,16.1,2.8,5.6,10.6,\"SSE\",50,\"SSE\",\"ESE\",20,28,68,49,1018.3,1018.5,7,7,11.1,15.4,\"Yes\",0,\"No\""Find those strings that contain a specific pattern using base::grep().
## [1] 3 10 23 26 28 36 37 42 43 49 50 54 68 69 71 76 86 91 97
## [20] 101 103 106 108 109 110 118 129 132 133 135 138 145 160 171 176 215 222 278
## [39] 303 304 310 323 341 348 351 357 365## [1] "2007-11-02,\"Canberra\",14,26.9,3.6,4.4,9.7,\"ENE\",39,\"E\",\"W\",4,17,80,36,1012.4,1008.4,5,3,17.5,25.7,\"Yes\",3.6,\"Yes\""
## [2] "2007-11-09,\"Canberra\",8.8,19.5,0,4,4.1,\"S\",48,\"E\",\"ENE\",19,17,70,48,1026.1,1022.7,7,7,14.1,18.9,\"No\",16.2,\"Yes\""
## [3] "2007-11-22,\"Canberra\",16.4,19.4,0.4,9.2,0,\"E\",26,\"ENE\",\"E\",6,11,88,72,1010.7,1008.9,8,8,16.5,18.3,\"No\",25.8,\"Yes\""
## [4] "2007-11-25,\"Canberra\",15.4,28.4,0,4.4,8.1,\"ENE\",33,\"SSE\",\"NE\",9,15,85,31,1022.4,1018.6,8,2,16.8,27.3,\"No\",0,\"No\""
## [5] "2007-11-27,\"Canberra\",13.3,22.2,0.2,6.6,2.3,\"ENE\",39,\"E\",\"E\",20,17,70,55,1021,1018.6,7,7,16.5,21.2,\"No\",0,\"No\""
## [6] "2007-12-05,\"Canberra\",14.5,21.8,0,8.4,9.8,\"ENE\",43,\"ESE\",\"E\",11,30,69,63,1015,1015.3,7,1,18.6,20.5,\"No\",0,\"No\""
## [7] "2007-12-06,\"Canberra\",16.3,26.8,0,6,6.3,\"ENE\",39,\"ESE\",\"ESE\",13,9,78,54,1018.8,1016.1,8,7,18.6,24.5,\"No\",0,\"No\""
## [8] "2007-12-11,\"Canberra\",11.8,18.5,0.6,4.8,2.3,\"ENE\",35,\"ESE\",\"E\",9,15,60,63,1018,1017.4,8,6,13.8,16.4,\"No\",0,\"No\""
## [9] "2007-12-12,\"Canberra\",11.7,21.5,0,4.2,7.3,\"ENE\",41,\"ESE\",\"E\",15,24,66,51,1021.1,1019.6,7,5,15.7,19.4,\"No\",0,\"No\""
## [10] "2007-12-18,\"Canberra\",7.5,20.9,0,6.6,8.7,\"ENE\",39,\"SE\",\"E\",13,20,61,43,1020.6,1018.3,6,7,15.3,19.8,\"No\",0,\"No\""
## [11] "2007-12-19,\"Canberra\",12.8,21,0,6.4,0.8,\"NE\",22,\"NE\",\"ENE\",7,6,72,54,1018,1015.6,8,8,16.1,20,\"No\",3.4,\"Yes\""
## [12] "2007-12-23,\"Canberra\",9.2,20.4,17.4,7.8,10.2,\"ENE\",39,\"N\",\"N\",9,20,59,49,1009.5,1009.1,1,7,14.9,18.8,\"Yes\",0,\"No\""
## [13] "2008-01-06,\"Canberra\",14.3,34.1,0,6.6,10.5,\"ENE\",39,\"W\",\"NNW\",6,19,77,34,1006.6,1003.3,1,1,18.9,31.9,\"No\",0,\"No\""
## [14] "2008-01-07,\"Canberra\",16.5,33.9,0,9,12.6,\"ENE\",39,\"E\",\"NW\",11,11,60,36,1012.3,1009.5,1,1,20.8,31.3,\"No\",0,\"No\""
## [15] "2008-01-09,\"Canberra\",17.5,29.9,0,6.6,8.8,\"E\",43,\"E\",\"ENE\",13,11,74,45,1018.5,1015.9,8,1,19.3,27.9,\"No\",0,\"No\""
## [16] "2008-01-14,\"Canberra\",16,22.8,0,12.4,6,\"E\",50,\"E\",\"ENE\",13,19,70,57,1012.3,1012.3,8,6,17,21.6,\"No\",0,\"No\""
## [17] "2008-01-24,\"Canberra\",10.3,27.8,0,6.4,9.9,\"ENE\",35,\"SE\",\"NE\",6,11,64,29,1021.3,1018.1,3,6,17,26.3,\"No\",0,\"No\""
## [18] "2008-01-29,\"Canberra\",17.9,33.9,0,10.4,11.8,\"ENE\",46,\"S\",\"W\",6,11,72,22,1017.4,1014.6,1,1,19.8,32.3,\"No\",0,\"No\""
## [19] "2008-02-04,\"Canberra\",18.2,22.6,1.8,8,0,\"ENE\",33,\"SSE\",\"ENE\",7,13,92,76,1014.4,1011.5,8,8,18.5,22.1,\"Yes\",9,\"Yes\""
## [20] "2008-02-08,\"Canberra\",12.4,19.9,16.2,5.4,5.6,\"ENE\",41,\"ESE\",\"ESE\",7,20,75,58,1007.6,1005,7,7,13.6,18.7,\"Yes\",0,\"No\""
## [21] "2008-02-10,\"Canberra\",9.1,23.1,0,5.8,9.6,\"ENE\",41,\"SSE\",\"W\",17,13,66,37,1013.6,1011.4,1,7,14,21.4,\"No\",0,\"No\""
## [22] "2008-02-13,\"Canberra\",12.6,18.2,11,3.2,0.4,\"ENE\",30,\"SSE\",\"SSE\",13,15,81,73,1010,1011,7,8,16.3,16.8,\"Yes\",0.2,\"No\""
## [23] "2008-02-15,\"Canberra\",10.8,25.2,0,5.6,12.6,\"ENE\",35,\"SE\",\"E\",7,7,69,32,1020.2,1016.7,1,1,15,24.3,\"No\",0,\"No\""
## [24] "2008-02-16,\"Canberra\",11.2,26.1,0,7.2,12.6,\"ENE\",39,\"SE\",\"E\",7,19,71,40,1022.9,1020,1,1,15.3,24.7,\"No\",0,\"No\""
## [25] "2008-02-17,\"Canberra\",12.1,24.1,0,7.4,10.2,\"ENE\",46,\"ESE\",\"NNE\",9,13,64,46,1025.2,1021.4,7,1,15.4,22.5,\"No\",0,\"No\""
## [26] "2008-02-25,\"Canberra\",11.5,25.9,0,5.2,10.2,\"ENE\",44,\"ENE\",\"WSW\",9,7,70,35,1016.4,1014.3,6,2,15.8,24.3,\"No\",0,\"No\""
## [27] "2008-03-07,\"Canberra\",10.8,29.2,0,8.4,7.5,\"E\",50,NA,\"ENE\",NA,9,56,34,1021.6,1017.7,0,7,17.5,27.7,\"No\",3,\"Yes\""
## [28] "2008-03-10,\"Canberra\",12.5,31.7,0,6.6,11.2,\"WNW\",24,\"ENE\",\"W\",6,9,74,28,1024.9,1020.4,1,1,17.2,30.1,\"No\",0,\"No\""
## [29] "2008-03-11,\"Canberra\",13.9,34.7,0,6.4,8.5,\"SSW\",46,\"SE\",\"ENE\",11,7,50,18,1022.8,1019.3,0,3,20.2,32.7,\"No\",0.2,\"No\""
## [30] "2008-03-13,\"Canberra\",13.2,33.1,0,8.6,9.7,\"ENE\",39,\"SE\",\"NNW\",7,7,91,18,1020.9,1017.7,7,1,16.1,31.7,\"No\",0,\"No\""
## [31] "2008-03-16,\"Canberra\",11.3,32.3,0,9.4,11.4,\"NE\",28,\"ENE\",\"WNW\",4,6,44,17,1024.3,1020.7,5,2,18.2,30.5,\"No\",0,\"No\""
## [32] "2008-03-23,\"Canberra\",12.8,24.9,0,2.4,6.2,\"ENE\",30,\"NNW\",\"SW\",6,7,76,44,1023.2,1019.3,7,6,15.5,24.2,\"No\",0.6,\"No\""
## [33] "2008-04-07,\"Canberra\",8.1,20.5,0,3.8,7.8,\"ENE\",31,\"ESE\",\"ENE\",11,11,66,48,1027.8,1024,1,5,14.9,19.5,\"No\",0,\"No\""
## [34] "2008-04-18,\"Canberra\",7.9,19.7,0,3.2,8.3,\"ESE\",48,\"SSE\",\"ENE\",17,11,58,43,1027.3,1024.1,3,6,14,19.1,\"No\",0,\"No\""
## [35] "2008-04-23,\"Canberra\",7.5,19,0,4,6.8,\"ENE\",26,NA,\"ESE\",0,7,74,43,1025.5,1022.2,6,5,12.6,18.1,\"No\",0,\"No\""
## [36] "2008-06-01,\"Canberra\",0.6,14,0,2.2,2.7,\"NE\",17,NA,\"ENE\",NA,7,99,67,1032.3,1028.9,7,7,4.6,13.9,\"No\",0,\"No\""
## [37] "2008-06-08,\"Canberra\",4.3,14.5,0,2,3,\"E\",30,\"SSE\",\"ENE\",6,13,76,70,1034.3,1031.7,7,7,7.9,13,\"No\",0,\"No\""
## [38] "2008-08-03,\"Canberra\",2.3,12.8,0,2.2,9.6,\"WNW\",35,\"ENE\",\"WNW\",4,24,70,48,1021.2,1018.1,1,1,7.8,11.6,\"No\",0,\"No\""
## [39] "2008-08-28,\"Canberra\",-0.1,14.7,0,3.4,9.9,\"ENE\",30,\"SE\",\"NE\",6,15,60,43,1029.9,1025.9,1,5,7.2,12.3,\"No\",0,\"No\""
## [40] "2008-08-29,\"Canberra\",-0.2,16.2,0,3.4,5.9,\"E\",28,NA,\"ENE\",0,20,74,45,1027.6,1022.9,7,6,7.3,14.6,\"No\",0,\"No\""
## [41] "2008-09-04,\"Canberra\",5.4,11.3,0.2,2.2,0.6,\"ENE\",35,\"SE\",\"ESE\",11,17,65,61,1035.7,1031.9,7,7,8.3,10.2,\"No\",0,\"No\""
## [42] "2008-09-17,\"Canberra\",0.7,14.1,0,5.6,9,\"ENE\",20,\"SSW\",\"NNW\",6,7,69,43,1026.7,1022.1,7,1,7.4,13.7,\"No\",0,\"No\""
## [43] "2008-10-05,\"Canberra\",10.3,21.3,3,4.2,6.7,\"NNW\",43,\"ENE\",\"N\",7,19,79,46,1018.1,1013.6,8,1,11.7,19.8,\"Yes\",0,\"No\""
## [44] "2008-10-12,\"Canberra\",4.5,23.9,0,4.8,11.7,\"NW\",30,\"ENE\",\"NNW\",4,11,67,27,1025.8,1021.5,0,4,12.6,22.3,\"No\",0,\"No\""
## [45] "2008-10-15,\"Canberra\",9.2,19.6,0.6,3.4,10.4,\"ENE\",31,\"SSE\",\"NNW\",4,7,71,42,1022.3,1019.7,7,4,11.6,18.4,\"No\",0,\"No\""
## [46] "2008-10-21,\"Canberra\",9,20.6,0,9,6.2,\"ENE\",39,\"S\",\"SW\",11,11,54,28,1022.3,1018.6,7,5,11.4,18.5,\"No\",0.8,\"No\""
## [47] "2008-10-29,\"Canberra\",12.5,19.9,0,8.4,5.3,\"ESE\",43,\"ENE\",\"ENE\",11,9,63,47,1024,1022.8,3,2,14.5,18.3,\"No\",0,\"No\""References
Williams, Graham. 2026. Rattle: R Data Science Supporting Rattle. https://togaware.com/projects/rattle/.
If you find this curated material useful then you can consider a donation to support it's ongoing availability and give you access to the PDF version of this book. The material has been scoped up by Generative AI without permission or any kind of recompense so do consider a donation if you can afford it. Unlike Generative AI your access to this materials is freely given. Desktop Survival Guides include Data Science, GNU/Linux, and MLHub. Books available on Amazon include Data Mining with Rattle and Essentials of Data Science. Togaware has a 30 year tradition of making popular open source software which includes sold privacy preserving productivity apps, rattle, wajig, and mlhub. Hosted by Togaware, a pioneer of free and open source software since 1984. Copyright © 1995-2022 Graham.Williams@togaware.com Creative Commons Attribution-ShareAlike 4.0
