Pendahuluan

Materi ini membahas dasar-dasar penggunaan bahasa pemrograman R, mulai dari menyimpan data dalam variabel menggunakan fungsi c(), mengakses dan mengubah data, penggunaan operator, jenis data, serta beberapa fungsi dasar dalam R.

Fungsi c()

simpan = c(10, 20, 40, 15, 40)

simpan
## [1] 10 20 40 15 40

Mengakses Nilai Data dalam Variabel secara Individual

simpan = c(10, 20, 40, 15, 40)

simpan
## [1] 10 20 40 15 40
simpan[3]
## [1] 40
simpan[4]
## [1] 15
simpan[c(1,3,4)]
## [1] 10 40 15
simpan[2:4]
## [1] 20 40 15

Mengubah Nilai Data dalam Variabel

simpan = c(10, 20, 40, 15, 40)
simpan
## [1] 10 20 40 15 40
simpan[3] = 100
simpan
## [1]  10  20 100  15  40
simpan[4] = 10000
simpan
## [1]    10    20   100 10000    40

Menghapus Nilai Data dalam Variabel

NILAI = c(10, 40, 45, 30, 80)
NILAI
## [1] 10 40 45 30 80
NILAI = NILAI[-3]
NILAI
## [1] 10 40 30 80
NILAI = NILAI[-4]
NILAI
## [1] 10 40 30
NILAI = NILAI[c(-1,-3)]
NILAI
## [1] 40

Penggunaan Operator > (Lebih Besar Dari)

NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI
##  [1] 100  95  70  80  25  60  80  60  55  90
NILAI[NILAI > 80]
## [1] 100  95  90

Penggunaan Operator < (Lebih Kecil Dari)

NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI
##  [1] 100  95  70  80  25  60  80  60  55  90
NILAI[NILAI < 70]
## [1] 25 60 60 55

Penggunaan Operator & (Dan)

NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI
##  [1] 100  95  70  80  25  60  80  60  55  90
NILAI[NILAI > 60 & NILAI < 80]
## [1] 70

Penggunaan Operator | (Atau)

NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI
##  [1] 100  95  70  80  25  60  80  60  55  90
NILAI[NILAI > 80 | NILAI < 30]
## [1] 100  95  25  90

Lebih Lanjut Penggunaan Operator < (Lebih Kecil Dari)

NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)

NILAI = NILAI[NILAI < 75]
NILAI
## [1] 70 25 60 60 55

Lebih Lanjut Penggunaan Operator > (Lebih Besar Dari)

NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)

NILAI = NILAI[NILAI > 90]
NILAI
## [1] 100  95

Contoh Sederhana Penggunaan dari Bahasa Pemrograman R

fungsi = function(x)
{
  for(i in 1:length(x))
  {
    if(x[i] < 65)
    {
      x[i] = x[i] + 10
    }
    print(x[i])
  }
}

A = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)

fungsi(A)
## [1] 100
## [1] 95
## [1] 70
## [1] 80
## [1] 35
## [1] 70
## [1] 80
## [1] 70
## [1] 65
## [1] 90

Jenis Data R

Berikut merupakan berbagai jenis dari jenis data dalam R. - Numeric atau angka - Character atau karakter - Logical atau logika - Function atau fungsi

#NUMERIC
mode(1000)
## [1] "numeric"
#CHARACTER
mode("HALO")
## [1] "character"
#LOGICAL
d = FALSE
mode(d)
## [1] "logical"
#FUNCTION
kuadrat = function(x)
{
  print(x*x)
}

A = c(4)

kuadrat(A)
## [1] 16
mode(kuadrat)
## [1] "function"

Operator Penjumlahan +, Pengurangan -, Perkalian *, Pembagian /, Pangkat ^, Sisa %%

A = c(2, 4, 6)

A + 2
## [1] 4 6 8
A - 2
## [1] 0 2 4
A * 2
## [1]  4  8 12
A / 2
## [1] 1 2 3
A ^ 2
## [1]  4 16 36
A %% 2
## [1] 0 0 0

Fungsi length

A = c(100,70,80,55,80,70,80)

length(A)
## [1] 7

Fungsi sort

A = c(70,80,50,25,100,60)

sort(A)
## [1]  25  50  60  70  80 100

Fungsi diff

A = c(100,50,70,80,60)

diff(A)
## [1] -50  20  10 -20

Fungsi sum

A = c(50,60,70,80)

sum(A)
## [1] 260

Fungsi sqrt

sqrt(81)
## [1] 9

Fungsi max dan min

A = c(10,25,90,75,95,57)

max(A)
## [1] 95
min(A)
## [1] 10

Fungsi exp

exp(1)
## [1] 2.718282
exp(2)
## [1] 7.389056

Fungsi pi atau 𝝅

pi
## [1] 3.141593

Fungsi options

options(digits=3)

pi
## [1] 3.14

Fungsi seq

seq(from=1, to=10)
##  [1]  1  2  3  4  5  6  7  8  9 10
seq(from=2, by=0.5, length.out=4)
## [1] 2.0 2.5 3.0 3.5

Fungsi panggil()

panggil = function(x,y,z)
{
  a = x
  print(a)

  for(i in x:z)
  {
    a = a + y

    if(a > z)
    {
      break
    }

    print(a)
  }
}

panggil(2,3,30)
## [1] 2
## [1] 5
## [1] 8
## [1] 11
## [1] 14
## [1] 17
## [1] 20
## [1] 23
## [1] 26
## [1] 29

Fungsi table

A = c(10,10,30,10,30,10,10,40,40,70,90,70,80,60,60,90)

table(A)
## A
## 10 30 40 60 70 80 90 
##  5  2  2  2  2  1  2
table(A)/length(A)
## A
##     10     30     40     60     70     80     90 
## 0.3125 0.1250 0.1250 0.1250 0.1250 0.0625 0.1250
hasil = c("ya","tidak","ya","ya","ya","ya","tidak","ya","tidak","ya")

table(hasil)
## hasil
## tidak    ya 
##     3     7
table(hasil)/length(hasil)
## hasil
## tidak    ya 
##   0.3   0.7

Fungsi factor

A = c("ikan","ikan","udang","ikan","udang","ikan","ikan","udang")

factor(A)
## [1] ikan  ikan  udang ikan  udang ikan  ikan  udang
## Levels: ikan udang
B = c("sarjana","diploma","sarjana","pengangguran",
      "sarjana","diploma","diploma","pengangguran")

factor(B)
## [1] sarjana      diploma      sarjana      pengangguran sarjana     
## [6] diploma      diploma      pengangguran
## Levels: diploma pengangguran sarjana

Fungsi barplot

A = c(10,10,10,10,20,20,30,30,30,30,30,30)

barplot(table(A))

barplot(table(A)/length(A))

# Fungsi plot

A = c(10,10,10,10,10,20,20,20,30,30,40)
table(A)
## A
## 10 20 30 40 
##  5  3  2  1
nilai = c(10,20,30,40)
frekuensi = c(5,3,2,1)
plot(nilai, frekuensi)

A = c(10,10,10,10,10,20,20,20,30,30,40)
plot(table(A))