R version 4.5.2 (2025-10-31 ucrt) -- "[Not] Part in a Rumble"
Copyright (C) 2025 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64

R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.

R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.

Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.

> x <- c(10,-4,8,13)
> x + 10
[1] 20  6 18 23
> rivers
  [1]  735  320  325  392  524  450 1459  135  465  600
 [11]  330  336  280  315  870  906  202  329  290 1000
 [21]  600  505 1450  840 1243  890  350  407  286  280
 [31]  525  720  390  250  327  230  265  850  210  630
 [41]  260  230  360  730  600  306  390  420  291  710
 [51]  340  217  281  352  259  250  470  680  570  350
 [61]  300  560  900  625  332 2348 1171 3710 2315 2533
 [71]  780  280  410  460  260  255  431  350  760  618
 [81]  338  981 1306  500  696  605  250  411 1054  735
 [91]  233  435  490  310  460  383  375 1270  545  445
[101] 1885  380  300  380  377  425  276  210  800  420
[111]  350  360  538 1100 1205  314  237  610  360  540
[121] 1038  424  310  300  444  301  268  620  215  652
[131]  900  525  246  360  529  500  720  270  430  671
[141] 1770
> #vlongrivers = rivers with length >=2000 
> vlongrivers.indx <- rivers >= 2000 
> vlongrivers.indx
  [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
  [9] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [17] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [25] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [33] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [41] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [49] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [57] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [65] FALSE  TRUE FALSE  TRUE  TRUE  TRUE FALSE FALSE
 [73] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [81] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [89] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
 [97] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[105] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[113] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[121] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[129] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[137] FALSE FALSE FALSE FALSE FALSE
> which(rivers)
Error in which(rivers) : argument to 'which' is not logical

> which(vlongrivers.indx)
[1] 66 68 69 70
> (1:141)[vlongrivers.indx]     #equivalent to which
[1] 66 68 69 70
> seq(from=5, to = 10, by=0.5)
 [1]  5.0  5.5  6.0  6.5  7.0  7.5  8.0  8.5  9.0  9.5
[11] 10.0
> seq(from=5, to = 10, by=-0.5)
Error in seq.default(from = 5, to = 10, by = -0.5) : 
  wrong sign in 'by' argument

> ?seq
> seq(from=5, to = 10, length.out=3)
[1]  5.0  7.5 10.0
> seq(from=5, to = 10, length.out=30)
 [1]  5.000000  5.172414  5.344828  5.517241  5.689655
 [6]  5.862069  6.034483  6.206897  6.379310  6.551724
[11]  6.724138  6.896552  7.068966  7.241379  7.413793
[16]  7.586207  7.758621  7.931034  8.103448  8.275862
[21]  8.448276  8.620690  8.793103  8.965517  9.137931
[26]  9.310345  9.482759  9.655172  9.827586 10.000000
> seq(length.out=3, to=10, from=5)
[1]  5.0  7.5 10.0
> seq(by=3, to=10, from=5)
[1] 5 8
> seq(from=5, to=10, by = 3)  #this is equivalent to above, as arguments are named
[1] 5 8
> seq(5, 10, 3 )   #this is a shortcut of the above
[1] 5 8
> seq(5, 10, ,3 )   #this is a shortcut of the above
[1]  5.0  7.5 10.0
> seq(from=5, to=10, length.out=3 )   #this is the full version
[1]  5.0  7.5 10.0
> seq(by=5, 10, 3 )
Error in seq.default(by = 5, 10, 3) : wrong sign in 'by' argument

> seq(1,20,length.out=100)
  [1]  1.000000  1.191919  1.383838  1.575758  1.767677
  [6]  1.959596  2.151515  2.343434  2.535354  2.727273
 [11]  2.919192  3.111111  3.303030  3.494949  3.686869
 [16]  3.878788  4.070707  4.262626  4.454545  4.646465
 [21]  4.838384  5.030303  5.222222  5.414141  5.606061
 [26]  5.797980  5.989899  6.181818  6.373737  6.565657
 [31]  6.757576  6.949495  7.141414  7.333333  7.525253
 [36]  7.717172  7.909091  8.101010  8.292929  8.484848
 [41]  8.676768  8.868687  9.060606  9.252525  9.444444
 [46]  9.636364  9.828283 10.020202 10.212121 10.404040
 [51] 10.595960 10.787879 10.979798 11.171717 11.363636
 [56] 11.555556 11.747475 11.939394 12.131313 12.323232
 [61] 12.515152 12.707071 12.898990 13.090909 13.282828
 [66] 13.474747 13.666667 13.858586 14.050505 14.242424
 [71] 14.434343 14.626263 14.818182 15.010101 15.202020
 [76] 15.393939 15.585859 15.777778 15.969697 16.161616
 [81] 16.353535 16.545455 16.737374 16.929293 17.121212
 [86] 17.313131 17.505051 17.696970 17.888889 18.080808
 [91] 18.272727 18.464646 18.656566 18.848485 19.040404
 [96] 19.232323 19.424242 19.616162 19.808081 20.000000
> ?rep
> rep(1:5, times=4)
 [1] 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5 1 2 3 4 5
> rep(1:5, each=4)
 [1] 1 1 1 1 2 2 2 2 3 3 3 3 4 4 4 4 5 5 5 5
> rep(c('a','b','c'), each=10)
 [1] "a" "a" "a" "a" "a" "a" "a" "a" "a" "a" "b" "b" "b"
[14] "b" "b" "b" "b" "b" "b" "b" "c" "c" "c" "c" "c" "c"
[27] "c" "c" "c" "c"
> rep(1:10,times=1:10)
 [1]  1  2  2  3  3  3  4  4  4  4  5  5  5  5  5  6  6  6
[19]  6  6  6  7  7  7  7  7  7  7  8  8  8  8  8  8  8  8
[37]  9  9  9  9  9  9  9  9  9 10 10 10 10 10 10 10 10 10
[55] 10
> rep(1:10,times=1:5)
Error in rep(1:10, times = 1:5) : invalid 'times' argument

> rep(1:10,3)    #shorthand version of abpve
 [1]  1  2  3  4  5  6  7  8  9 10  1  2  3  4  5  6  7  8
[19]  9 10  1  2  3  4  5  6  7  8  9 10
> ?sort
> 
> 
> 
> #character vectors
> xchar <- c('605','103','23','-8')
> xchar
[1] "605" "103" "23"  "-8" 
> xchar2 <- c('Male','Female','Male','Male')
> char2
Error: object 'char2' not found

> xchar2
[1] "Male"   "Female" "Male"   "Male"  
> xchar2 - 10
Error in xchar2 - 10 : non-numeric argument to binary operator

> xchar - 10
Error in xchar - 10 : non-numeric argument to binary operator

> as.numeric(xchar)
[1] 605 103  23  -8
> as.numeric(xchar2)
[1] NA NA NA NA
Warning message:
NAs introduced by coercion 

> #lets introduce 1 or 2 built-in character vectors
> letters
 [1] "a" "b" "c" "d" "e" "f" "g" "h" "i" "j" "k" "l" "m"
[14] "n" "o" "p" "q" "r" "s" "t" "u" "v" "w" "x" "y" "z"
> LETTERS
 [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" "K" "L" "M"
[14] "N" "O" "P" "Q" "R" "S" "T" "U" "V" "W" "X" "Y" "Z"
> month.abb
 [1] "Jan" "Feb" "Mar" "Apr" "May" "Jun" "Jul" "Aug" "Sep"
[10] "Oct" "Nov" "Dec"
> letters > 'm'
 [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[10] FALSE FALSE FALSE FALSE  TRUE  TRUE  TRUE  TRUE  TRUE
[19]  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE  TRUE
> xchar2
[1] "Male"   "Female" "Male"   "Male"  
> xchar2 == 'Male'
[1]  TRUE FALSE  TRUE  TRUE
> sum(xchar2 == 'Male')
[1] 3
> 
> 
> paste('no',1:10)
 [1] "no 1"  "no 2"  "no 3"  "no 4"  "no 5"  "no 6" 
 [7] "no 7"  "no 8"  "no 9"  "no 10"
> paste(1:5,seq(10,50,10))
[1] "1 10" "2 20" "3 30" "4 40" "5 50"
> paste(1:5, seq(10,50,10), sep='*')
[1] "1*10" "2*20" "3*30" "4*40" "5*50"
> paste(1:5, seq(10,50,10), sep='abcd')
[1] "1abcd10" "2abcd20" "3abcd30" "4abcd40" "5abcd50"
> paste(1:5, seq(10,50,10), sep='')
[1] "110" "220" "330" "440" "550"
> 
> #useful for labelling, eg
> #c('label1','label2',...'label50')   #slow way
> paste('label',1:50,sep='')
 [1] "label1"  "label2"  "label3"  "label4"  "label5" 
 [6] "label6"  "label7"  "label8"  "label9"  "label10"
[11] "label11" "label12" "label13" "label14" "label15"
[16] "label16" "label17" "label18" "label19" "label20"
[21] "label21" "label22" "label23" "label24" "label25"
[26] "label26" "label27" "label28" "label29" "label30"
[31] "label31" "label32" "label33" "label34" "label35"
[36] "label36" "label37" "label38" "label39" "label40"
[41] "label41" "label42" "label43" "label44" "label45"
[46] "label46" "label47" "label48" "label49" "label50"
> v <- paste('label',1:50,sep='')
> sum(v == 'label39')
[1] 1
> rivers1to10 <- rivers[1:10]
> rivers1to10
 [1]  735  320  325  392  524  450 1459  135  465  600
> sort(rivers1to10)
 [1]  135  320  325  392  450  465  524  600  735 1459
> order(rivers1to10)
 [1]  8  2  3  4  6  9  5 10  1  7
> rank(rivers1to10)
 [1]  9  2  3  4  7  5 10  1  6  8
> 
> 
> sort(rivers1to10, decreasing=T)
 [1] 1459  735  600  524  465  450  392  325  320  135
> sort(rivers1to10, T)
 [1] 1459  735  600  524  465  450  392  325  320  135
> rank(c(5,10,2,6,9))
[1] 2 5 1 3 4
> rank(c(5,10,2,5,9))
[1] 2.5 5.0 1.0 2.5 4.0
> rank(c(5,10,5,5,9))
[1] 2 5 2 2 4
> ?rank
> rank(c(5,10,2,5,9))
[1] 2.5 5.0 1.0 2.5 4.0
> rivers1to10
 [1]  735  320  325  392  524  450 1459  135  465  600
> as.character(rivers1to10)
 [1] "735"  "320"  "325"  "392"  "524"  "450"  "1459"
 [8] "135"  "465"  "600" 
> 
> 
> letters == 'c'
 [1] FALSE FALSE  TRUE FALSE FALSE FALSE FALSE FALSE FALSE
[10] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[19] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
> letters == c('b','c')
 [1] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[10] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE
[19] FALSE FALSE FALSE FALSE FALSE FALSE FALSE FALSE