R maksimum va minimum

Maksimum va minimum

Oldingi bobda mtcars ma’lumotlar to‘plami bilan tanishdik. Keyingi sahifalarda ham shu ma’lumotlar to‘plamidan foydalanishda davom etamiz.

R matematika bobidan R’da bir nechta o‘rnatilgan matematik funksiyalar borligini bilib oldingiz. Masalan, min() va max() funksiyalari to‘plamdagi eng kichik yoki eng katta qiymatni topish uchun ishlatilishi mumkin:

Misol

hp (ot kuchi) o‘zgaruvchisining eng katta va eng kichik qiymatini toping.

Data_Cars <- mtcars max(Data_Cars$hp) min(Data_Cars$hp)

Natija:


[1] 335

[1] 52

O‘zingiz sinab ko‘ring »

Endi to‘plamdagi eng katta ot kuchi qiymati 335, eng kichigi esa 52 ekanini bilamiz.

Bu ikki qiymat qaysi avtomobilga tegishli ekanini bilish uchun ma’lumotlar to‘plamini ko‘zdan kechirib chiqishimiz mumkin:

Avtomobillar kuzatuvi

                     mpg cyl  disp  hp drat    wt  qsec vs am gear carb
Mazda RX4           21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag       21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
Datsun 710          22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive      21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout   18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2
Valiant             18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1
Duster 360          14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4
Merc 240D           24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2
Merc 230            22.8   4 140.8  95 3.92 3.150 22.90  1  0    4    2
Merc 280            19.2   6 167.6 123 3.92 3.440 18.30  1  0    4    4
Merc 280C           17.8   6 167.6 123 3.92 3.440 18.90  1  0    4    4
Merc 450SE          16.4   8 275.8 180 3.07 4.070 17.40  0  0    3    3
Merc 450SL          17.3   8 275.8 180 3.07 3.730 17.60  0  0    3    3
Merc 450SLC         15.2   8 275.8 180 3.07 3.780 18.00  0  0    3    3
Cadillac Fleetwood  10.4   8 472.0 205 2.93 5.250 17.98  0  0    3    4
Lincoln Continental 10.4   8 460.0 215 3.00 5.424 17.82  0  0    3    4
Chrysler Imperial   14.7   8 440.0 230 3.23 5.345 17.42  0  0    3    4
Fiat 128            32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
Honda Civic         30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
Toyota Corolla      33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
Toyota Corona       21.5   4 120.1  97 3.70 2.465 20.01  1  0    3    1
Dodge Challenger    15.5   8 318.0 150 2.76 3.520 16.87  0  0    3    2
AMC Javelin         15.2   8 304.0 150 3.15 3.435 17.30  0  0    3    2
Camaro Z28          13.3   8 350.0 245 3.73 3.840 15.41  0  0    3    4
Pontiac Firebird    19.2   8 400.0 175 3.08 3.845 17.05  0  0    3    2
Fiat X1-9           27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
Porsche 914-2       26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
Lotus Europa        30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2
Ford Pantera L      15.8   8 351.0 264 4.22 3.170 14.50  0  1    5    4
Ferrari Dino        19.7   6 145.0 175 3.62 2.770 15.50  0  1    5    6
Maserati Bora       15.0   8 301.0 335 3.54 3.570 14.60  0  1    5    8
Volvo 142E          21.4   4 121.0 109 4.11 2.780 18.60  1  1    4    2

Jadvalni kuzatib, eng katta hp qiymati Maserati Bora’ga, eng kichigi esa Honda Civic’ga tegishli ekanini ko‘rish mumkin.

Biroq buni R’ning o‘ziga aniqlatish ancha oson (va ishonchliroq).

Masalan, jadvaldagi maksimal va minimal qiymatlarning indeks o‘rnini topish uchun which.max() va which.min() funksiyalaridan foydalanishimiz mumkin:

Misol

Data_Cars <- mtcars which.max(Data_Cars$hp) which.min(Data_Cars$hp)

Natija:


[1] 31

[1] 19

O‘zingiz sinab ko‘ring »

Yoki undan ham yaxshisi, eng katta va eng kichik ot kuchiga ega avtomobil nomini olish uchun which.max() va which.min() funksiyalarini rownames() funksiyasi bilan birlashtiring:

Misol

Data_Cars <- mtcars rownames(Data_Cars)[which.max(Data_Cars$hp)] rownames(Data_Cars)[which.min(Data_Cars$hp)]

Natija:


[1] "Maserati Bora"

[1] "Honda Civic"

O‘zingiz sinab ko‘ring »

Endi aniq bilamiz:
Maserati Bora — eng yuqori ot kuchiga ega avtomobil, Honda Civic esa eng past ot kuchiga ega avtomobil.

Chetga chiquvchi qiymatlar (outliers)

Max va min yordamida chetga chiquvchi qiymatlarni (outliers) ham aniqlash mumkin. Chetga chiquvchi qiymat — qolgan kuzatuvlardan farq qiladigan ma’lumot nuqtasi.

mtcars ma’lumotlar to‘plamida chetga chiquvchi qiymat bo‘lishi mumkin bo‘lgan ma’lumot nuqtalariga misollar:

Agar avtomobildagi oldinga yurish uzatmalarining maksimal soni 11 ta bo‘lganida
Agar avtomobilning minimal ot kuchi 0 bo‘lganida
Agar avtomobilning maksimal og‘irligi 50 000 funt bo‘lganida

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