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uni/year2/semester1/logseq-stuff/pages/Using R as a Calculator.md

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title:: Using R as a Calculator

  • #ST2001 Labs
  • Previous Topic: null
  • Next Topic: Describing Data in R
  • No relevant slides

  • Basic Algebra in R

    • Addition #card

      card-last-interval:: 33.64 card-repeats:: 4 card-ease-factor:: 2.9 card-next-schedule:: 2022-12-18T07:44:00.469Z card-last-reviewed:: 2022-11-14T16:44:00.470Z card-last-score:: 5 
      • # to add numbers in R, simply use "+"
2+2
      • Output: 
        • [1] 4

    • Subtraction #card

      card-last-interval:: 33.64 card-repeats:: 4 card-ease-factor:: 2.9 card-next-schedule:: 2022-12-18T07:44:48.506Z card-last-reviewed:: 2022-11-14T16:44:48.506Z card-last-score:: 5 
      • # to subtract numbers in R, simply use "-"
4-2
      • Output: 
        • [1] 2

    • Multiplication #card

      card-last-interval:: 33.64 card-repeats:: 4 card-ease-factor:: 2.9 card-next-schedule:: 2022-12-18T07:46:18.737Z card-last-reviewed:: 2022-11-14T16:46:18.738Z card-last-score:: 5 
      • # to multiply numbers in R, simply use "*"
5*2
      • Output: 
        • [1] 10

    • Division #card

      card-last-interval:: 33.64 card-repeats:: 4 card-ease-factor:: 2.9 card-next-schedule:: 2022-11-22T23:24:36.469Z card-last-reviewed:: 2022-10-20T08:24:36.470Z card-last-score:: 5 
      • # to divide numbers in R, simply use "/"
10/5
      • Output: 
        • [1] 2

    • Exponents #card

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      • # use "^" to raise a number to a power
3^2
3^{-1} # use curly braces
      • Output: 
        • [1] 9
[1] 0.3333333

    • Square Roots #card

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      • # use the function "sqrt()" to get the square root of a number in R
sqrt(16)
      • Output: 
        • [1] 4

    • Modulus #card

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      • # use "%%" to get the modulus
19%%6
        • Output: 
          • [1] 1

  • Rounding in R

    • Absolute Value #card

      card-last-interval:: 33.64 card-repeats:: 4 card-ease-factor:: 2.9 card-next-schedule:: 2022-12-18T07:44:02.326Z card-last-reviewed:: 2022-11-14T16:44:02.327Z card-last-score:: 5 
      • # use "abs()" to get absolute value in R
abs(-1)
        • Output: 
          • [1] 1

    • Rounding #card

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      • The function round() in R goes not necessarily do what you would expect when rounding numbers ending in .5 - ^^it rounds to the nearest even number.^^
        • If you always round up numbers ending in .5, then you are causing an upwards bias.
        • The rounding to even numbers will tend to average out at a zero bias, as 50% go up and 50% go down.
      • # use "round()" to round
round(1.5)
round(0.5)
round(0.7)
        • Output: 
          • [1] 2
[1] 0
[1] 1

  • \pi in R #card

    card-last-interval:: 33.64 card-repeats:: 4 card-ease-factor:: 2.9 card-next-schedule:: 2022-12-18T07:38:10.483Z card-last-reviewed:: 2022-11-14T16:38:10.484Z card-last-score:: 5 
    • # to get pi in R, simply use the in-built constant "pi"
pi
    • Output: 
      • [1] 3.141593

  • Trigonometric Functions in R

    • Sine in R #card

      card-last-interval:: 33.64 card-repeats:: 4 card-ease-factor:: 2.9 card-next-schedule:: 2022-12-15T02:31:07.981Z card-last-reviewed:: 2022-11-11T11:31:07.981Z card-last-score:: 5 
      • # to get the sine of a number in R, use the function "sin()"
sin(0.5 * pi)
sin(pi)
      • Output: 
        • [1] 1
[1] 1.224647e-16
        • ^^Note:^^ 1.224606e-16 \approx 0. Due to the way computers store numbers, decimals are often slightly off, so sine(\pi) \ne 0 even though it should, of course, be equal to zero. Be careful of this!

    • Cosine in R #card

      card-last-interval:: 33.64 card-repeats:: 4 card-ease-factor:: 2.9 card-next-schedule:: 2022-12-18T07:45:11.108Z card-last-reviewed:: 2022-11-14T16:45:11.109Z card-last-score:: 5 
      • # use "cos()" to get cosine
cos(0)
        • Output: 
          • [1] 1

    • Tangent in R #card

      card-last-interval:: 33.64 card-repeats:: 4 card-ease-factor:: 2.9 card-next-schedule:: 2022-12-18T07:51:39.012Z card-last-reviewed:: 2022-11-14T16:51:39.012Z card-last-score:: 5 
      • # use "tan()" to get tangent
tan(0)
      • Output: 
        • [1] 0

  • Logarithms in R

    • Natural Log #card

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      • log(1)
      • Output:
        • ```R` [1] 0

    • Logs to a Given Base #card

      card-last-interval:: 4 card-repeats:: 2 card-ease-factor:: 2.66 card-next-schedule:: 2022-11-22T18:34:16.626Z card-last-reviewed:: 2022-11-18T18:34:16.626Z card-last-score:: 5 
      • # log<base>()
log10(100)
      • Output: 
        • [1] 2