R version 4.5.2 (2025-10-31 ucrt) -- "[Not] Part in a Rumble"
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Platform: x86_64-w64-mingw32/x64

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> rivers10 <- rivers[1:10]     #first ten values of rivers
> rivers10
 [1]  735  320  325  392  524  450 1459  135  465  600
> rivers10[1] <- NA
> rivers10[5] <- NA
> rivers10
 [1]   NA  320  325  392   NA  450 1459  135  465  600
> is.na(rivers10)
 [1]  TRUE FALSE FALSE FALSE  TRUE FALSE FALSE FALSE FALSE
[10] FALSE
> sum(is.na(rivers10))
[1] 2
> 
> 
> 10 * (5 > 1)
[1] 10
> 10
[1] 10
> 5 > 1
[1] TRUE
> 10 * TRUE
[1] 10
> airquality$Ozone
  [1]  41  36  12  18  NA  28  23  19   8  NA   7  16  11
 [14]  14  18  14  34   6  30  11   1  11   4  32  NA  NA
 [27]  NA  23  45 115  37  NA  NA  NA  NA  NA  NA  29  NA
 [40]  71  39  NA  NA  23  NA  NA  21  37  20  12  13  NA
 [53]  NA  NA  NA  NA  NA  NA  NA  NA  NA 135  49  32  NA
 [66]  64  40  77  97  97  85  NA  10  27  NA   7  48  35
 [79]  61  79  63  16  NA  NA  80 108  20  52  82  50  64
 [92]  59  39   9  16  78  35  66 122  89 110  NA  NA  44
[105]  28  65  NA  22  59  23  31  44  21   9  NA  45 168
[118]  73  NA  76 118  84  85  96  78  73  91  47  32  20
[131]  23  21  24  44  21  28   9  13  46  18  13  24  16
[144]  13  23  36   7  14  30  NA  14  18  20
> sum(is.na(airquality$Ozone))
[1] 37
> 
> 
> mean(is.na(airquality$Ozone))
[1] 0.2418301
> 
> 
> 
> factorial(5)
[1] 120
> factorial(50)
[1] 3.041409e+64
> factorial(4)
[1] 24
> factorial(4.5)
[1] 52.34278
> 
> 
> #exploring gamma function
> gamma(3)
[1] 2
> gamma(4)
[1] 6
> gamma(5)
[1] 24
> gamma(6)
[1] 120
> gamma(11)-factorial(10)
[1] 0
> gamma(11)
[1] 3628800
> log(gamma(11))
[1] 15.10441
> factorial(100)
[1] 9.332622e+157
> factorial(200)
[1] Inf
> factorial(180)
[1] Inf
> factorial(170)
[1] 7.257416e+306
> factorial(175)
[1] Inf
> factorial(174)
[1] Inf
> factorial(173)
[1] Inf
> factorial(172)
[1] Inf
> factorial(171)
[1] Inf
> factorial(170)
[1] 7.257416e+306
> 
> 
> log(factorial(190))
[1] Inf
> log(Inf)
[1] Inf
> gamma(191)    #is equivalent to 190! but through gamma function
[1] Inf
> 
> lgamma(191)
[1] 810.4775
> lgamma
function (x)  .Primitive("lgamma")
> factorial
function (x) 
gamma(x + 1)
<bytecode: 0x00000220450963e0>
<environment: namespace:base>
> sum(log(1:190))
[1] 810.4775
> 
> 
> round(5.8)
[1] 6
> round(5.4)
[1] 5
> 
> 
> ceiling(5.8)
[1] 6
> ceiling(5.3)
[1] 6
> ceiling(5.00001)
[1] 6
> 
> 
> floor(5.00001)
[1] 5
> floor(5.8)
[1] 5
> floor(5.9999999)
[1] 5
> 
> 
> 
> #We have seen built-in functions in R. How about built-in constants?
> pi
[1] 3.141593
> print(pi, digits=100)
Error in print.default(pi, digits = 100) : invalid printing digits 100

> ?print
> print(pi, digits=20)
[1] 3.141592653589793116
> e
Error: object 'e' not found

> exp(1)
[1] 2.718282
> i
Error: object 'i' not found

> sqrt(-1)
[1] NaN
Warning message:
In sqrt(-1) : NaNs produced

> 1i
[1] 0+1i
> 1*i
Error: object 'i' not found

> 
> 
> rm(rivers)
Warning message:
In rm(rivers) : object 'rivers' not found

> pi
[1] 3.141593
> rm(pi)
Warning message:
In rm(pi) : object 'pi' not found

> pi <- 10
> 2*pi-3
[1] 17
> rm(pi)
> pi
[1] 3.141593
> 
> 
> x <- TRUE
> y <- FALSE
> 
> x&y
[1] FALSE
> TRUE <- 10 
Error in TRUE <- 10 : invalid (do_set) left-hand side to assignment

> x1 <- T
> x2 <- F
> T <- 20
> x3 <- T
> !x1
[1] FALSE
> !x3
[1] FALSE
>