BAB 2: FUNGSI DASAR DALAM R

Dokumen R Markdown ini berisi rangkuman materi dan latihan fungsi-fungsi dasar dalam R berdasarkan Bab 2 dari guidebook Belajar Statistika dengan R (Gio & Irawan, 2016).

# 1. Menyimpan Data dalam Variabel (Fungsi c())
simpan = c(10, 20, 40, 15, 40)
simpan
## [1] 10 20 40 15 40
simpan = c(1000, 2000, 3000, 4000, 5000)
simpan
## [1] 1000 2000 3000 4000 5000
# 2. Mengakses Nilai Data dalam Variabel 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 dalam Variabel
simpan = c(10, 20, 40, 15, 40)
simpan[3] = 100
simpan[4] = 10000
simpan
## [1]    10    20   100 10000    40
# 4. 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
# 5. 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
# 6. Penggunaan Operator < (Lebih Kecil Dari)
NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI[NILAI < 70]
## [1] 25 60 60 55
# 7. Penggunaan Operator & (Dan)
NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI[NILAI > 60 & NILAI < 80]
## [1] 70
# 8. Penggunaan Operator | (Atau)
NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI[NILAI > 80 | NILAI < 30]
## [1] 100  95  25  90
# 9. Lebih Lanjut Penggunaan Operator < dan >
# Menghapus nilai yang >= 75
NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI = NILAI[NILAI < 75]
NILAI
## [1] 70 25 60 60 55
# Menghapus nilai yang <= 90
NILAI = c(100, 95, 70, 80, 25, 60, 80, 60, 55, 90)
NILAI = NILAI[NILAI > 90]
NILAI
## [1] 100  95
# 10. Contoh Sederhana Bahasa Pemrograman R (Function, For, dan If)
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
# 11. Jenis Data R (numeric, character, logical, function)
mode(1000)
## [1] "numeric"
simpan = c(1000)
mode(simpan)
## [1] "numeric"
mode("HALO")
## [1] "character"
simpan = c("HALO")
mode(simpan)
## [1] "character"
d = c(F)
d
## [1] FALSE
a = c(T)
a
## [1] TRUE
mode(d)
## [1] "logical"
mode(a)
## [1] "logical"
kuadrat = function(x) {
  print(x * x)
}
A = c(4)
kuadrat(A)
## [1] 16
mode(kuadrat)
## [1] "function"
# 12. Operator Matematika
A = c(1, 2, 3)
B = c(4, 5, 6)
C = A + B
C
## [1] 5 7 9
A = c(2, 4, 6)
B = c(1, 3, 5)
B - A
## [1] -1 -1 -1
A = c(4, 8, 12)
A * 0.5
## [1] 2 4 6
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
# 13. Fungsi length()
A = c(100, 70, 80, 55, 80, 70, 80)
length(A)
## [1] 7
# 14. Fungsi sort()
A = c(70, 80, 50, 25, 100, 60)
sort(A)
## [1]  25  50  60  70  80 100
# 15. Fungsi diff()
A = c(100, 50, 70, 80, 60)
diff(A)
## [1] -50  20  10 -20
# 16. Fungsi sum()
A = c(50, 60, 70, 80)
sum(A)
## [1] 260
# 17. Fungsi sqrt()
a = sqrt(81)
a
## [1] 9
b = sqrt(a)
b
## [1] 3
# 18. Fungsi max() dan min()
A = c(10, 25, 90, 75, 95, 57)
max(A)
## [1] 95
min(A)
## [1] 10
# 19. Fungsi exp()
exp(1)
## [1] 2.718282
exp(2)
## [1] 7.389056
# 20. Fungsi pi
pi
## [1] 3.141593
# 21. Fungsi options()
options(digits = 3)
pi
## [1] 3.14
options(digits = 10)
pi
## [1] 3.141592654
# 22. 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
seq(2, 30, 3)
##  [1]  2  5  8 11 14 17 20 23 26 29
# 23. 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
# 24. 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
# 25. Fungsi barplot()
A = c(10, 10, 10, 10, 20, 20, 30, 30, 30, 30, 30, 30)
barplot(table(A))

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

# 26. Fungsi plot()
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))