BAB 2 STATISTIK SOSIAL

Menyimpan dan Mengeksekusi Data Dalam Variabel

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

Mengeksekusi Kode R

simpan <- c(10, 20, 40, 15, 40)
simpan[c(1, 3, 4)]
## [1] 10 40 15
simpan
## [1] 10 20 40 15 40

Mengakses Nilai Data dalam Variabel secara Individual

simpan <- c(10, 20, 40, 15, 40)
simpan[3]
## [1] 40
simpan[4]
## [1] 15
simpan
## [1] 10 20 40 15 40

Mengubah Nilai Data Dalam Variabel

simpan <- c(10, 20, 40, 15, 40)
simpan[3] <- 100
simpan[4] <- 1000
simpan
## [1]   10   20  100 1000   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
NILAI
##  [1] 100  95  70  80  25  60  80  60  55  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
NILAI
##  [1] 100  95  70  80  25  60  80  60  55  90

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
NILAI
##  [1] 100  95  70  80  25  60  80  60  55  90

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
NILAI
##  [1] 100  95  70  80  25  60  80  60  55  90

Lebih Lanjut 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[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
##  [1] 100  95  70  80  25  60  80  60  55  90
NILAI <- NILAI[NILAI > 90]
NILAI
## [1] 100  95

Contoh Sederhana Penggunaan Bahasa Pemrograman R

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

Numeric

mode(1000)
## [1] "numeric"
simpan <- c(1000)
mode(simpan)
## [1] "numeric"

Character

mode("Halo")
## [1] "character"
simpan <- c("Halo")
mode(simpan)
## [1] "character"

Logical

d <- c(FALSE)
d
## [1] FALSE
a <- c(TRUE)
a
## [1] TRUE
mode(d)
## [1] "logical"
mode(a)
## [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, dan Sisa

A <- c(1, 2, 3)
B <- c(4, 5, 6)
C <- A + B
C
## [1] 5 7 9
A <- c(1, 2, 3)
B <- 2 + A
B
## [1] 3 4 5
A <- c(2, 4, 6)
B <- c(1, 3, 5)
B - A
## [1] -1 -1 -1
A <- c(4, 8, 12)
B <- c(2, 2, 2)
A / B
## [1] 2 4 6
A <- c(3, 6, 1)
B <- c(2, 2, 0)
A ^ B
## [1]  9 36  1
A <- c(5, 2, 7)
B <- c(3, 2, 6)
C <- A %% B
C
## [1] 2 0 1

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

a <- sqrt(81)
a
## [1] 9
b <- sqrt(a)
b
## [1] 3

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
options(digits = 10)
pi
## [1] 3.141592654

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

Cara lain

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

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))