1. Menyimpan Data dalam Variabel (Fungsi c)

simpan = c(10, 20, 40, 15, 40)
simpan
## [1] 10 20 40 15 40

2. Mengakses Nilai Data secara Individual

simpan = c(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

3. Mengubah Nilai Data

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

4. Menghapus Nilai Data

NILAI = c(10, 40, 45, 30, 80)
NILAI = NILAI[-3]        # hapus nilai 45
NILAI
## [1] 10 40 30 80
NILAI = NILAI[-4]        # hapus nilai 80
NILAI
## [1] 10 40 30
NILAI = NILAI[c(-1,-3)]  # hapus posisi ke-1 dan ke-3
NILAI
## [1] 40

5. Operator Perbandingan dan Logika

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

NILAI[NILAI > 80]               # lebih besar dari 80
## [1] 100  95  90
NILAI[NILAI < 70]               # lebih kecil dari 70
## [1] 25 60 60 55
NILAI[NILAI > 60 & NILAI < 80]  # DAN
## [1] 70
NILAI[NILAI > 80 | NILAI < 30]  # ATAU
## [1] 100  95  25  90

6. Menghapus Nilai Berdasarkan Syarat

NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI = NILAI[NILAI < 75]   # hapus nilai >= 75
NILAI
## [1] 70 25 60 60 55
NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI = NILAI[NILAI > 90]   # hapus nilai <= 90
NILAI
## [1] 100  95

7. Contoh Sederhana Program R

Nilai yang lebih kecil dari 65 ditambah 10.

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

8. Jenis Data R

mode(1000)      # numeric
## [1] "numeric"
mode("HALO")    # character
## [1] "character"
d = (F)
mode(d)         # logical
## [1] "logical"
kuadrat = function(x)
{
  print(x*x)
}
A = c(4)
kuadrat(A)
## [1] 16
mode(kuadrat)   # function
## [1] "function"

9. Operator Matematika

10 + 5    # penjumlahan
## [1] 15
10 - 5    # pengurangan
## [1] 5
10 * 5    # perkalian
## [1] 50
10 / 4    # pembagian
## [1] 2.5
2 ^ 3     # pangkat
## [1] 8
10 %% 3   # sisa bagi
## [1] 1

10. Fungsi length

A = c(100, 70, 80, 55, 80, 70, 80)
length(A)
## [1] 7

11. Fungsi sort

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

12. Fungsi diff

A = c(100, 50, 70, 80, 60)
diff(A)
## [1] -50  20  10 -20

13. Fungsi sum

A = c(50, 60, 70, 80)
sum(A)
## [1] 260

14. Fungsi sqrt

sqrt(81)
## [1] 9

15. Fungsi max dan min

A = c(10, 25, 90, 75, 95, 57)
max(A)
## [1] 95
min(A)
## [1] 10

16. Fungsi exp

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

17. Fungsi pi

pi
## [1] 3.141593

18. Fungsi options

options(digits = 3)
pi
## [1] 3.14
options(digits = 7)   # kembalikan ke bawaan

19. 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
# Kelipatan 3 dari 2 sampai 30 (dengan fungsi buatan sendiri)
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
# Cara lain (lebih singkat)
seq(from = 2, to = 30, by = 3)
##  [1]  2  5  8 11 14 17 20 23 26 29

20. 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

21. 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
A = c("sarjana", "diploma", "sarjana", "pengangguran", "sarjana", "diploma",
      "diploma", "pengangguran")
factor(A)
## [1] sarjana      diploma      sarjana      pengangguran sarjana     
## [6] diploma      diploma      pengangguran
## Levels: diploma pengangguran sarjana

22. Fungsi barplot

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

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

23. 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)

# Alternatif
plot(table(A))