Indeks eksplisit

Manipulasi Data dengan pandas

Richie Cotton

Data Evangelist at DataCamp

Kumpulan data anjing, ditinjau kembali

print(dogs)

      name        breed  color  height_cm  weight_kg
0    Bella     Labrador  Brown         56         25
1  Charlie       Poodle  Black         43         23
2     Lucy    Chow Chow  Brown         46         22
3   Cooper    Schnauzer   Gray         49         17
4      Max     Labrador  Black         59         29
5   Stella    Chihuahua    Tan         18          2
6   Bernie  St. Bernard  White         77         74

.kolom dan .indeks

dogs.columns

Index(['name', 'breed', 'color', 'height_cm', 'weight_kg'], dtype='object')

dogs.index

RangeIndex(start=0, stop=7, step=1)

Menetapkan kolom sebagai indeks

dogs_ind = dogs.set_index("name")

print(dogs_ind)

               breed  color  height_cm  weight_kg
name                                             
Bella       Labrador  Brown         56         25
Charlie       Poodle  Black         43         23
Lucy       Chow Chow  Brown         46         22
Cooper     Schnauzer   Grey         49         17
Max         Labrador  Black         59         29
Stella     Chihuahua    Tan         18          2
Bernie   St. Bernard  White         77         74

Menghapus indeks

dogs_ind.reset_index()

      name        breed  color  height_cm  weight_kg
0    Bella     Labrador  Brown         56         25
1  Charlie       Poodle  Black         43         23
2     Lucy    Chow Chow  Brown         46         22
3   Cooper    Schnauzer   Grey         49         17
4      Max     Labrador  Black         59         29
5   Stella    Chihuahua    Tan         18          2
6   Bernie  St. Bernard  White         77         74

Menghapus indeks secara permanen

dogs_ind.reset_index(drop=True)

         breed  color  height_cm  weight_kg
0     Labrador  Brown         56         25
1       Poodle  Black         43         23
2    Chow Chow  Brown         46         22
3    Schnauzer   Grey         49         17
4     Labrador  Black         59         29
5    Chihuahua    Tan         18          2
6  St. Bernard  White         77         74

Indeks memudahkan proses malakukan subset.

dogs[dogs["name"].isin(["Bella", "Stella"])]

     name      breed  color  height_cm  weight_kg
0   Bella   Labrador  Brown         56         25
5  Stella  Chihuahua    Tan         18          2

dogs_ind.loc[["Bella", "Stella"]]

            breed  color  height_cm  weight_kg
name                                          
Bella    Labrador  Brown         56         25
Stella  Chihuahua    Tan         18          2

Nilai indeks tidak perlu unik.

dogs_ind2 = dogs.set_index("breed")
print(dogs_ind2)

                name  color  height_cm  weight_kg
breed                                            
Labrador       Bella  Brown         56         25
Poodle       Charlie  Black         43         23
Chow Chow       Lucy  Brown         46         22
Schnauzer     Cooper   Grey         49         17
Labrador         Max  Black         59         29
Chihuahua     Stella    Tan         18          2
St. Bernard   Bernie  White         77         74

Melakukan subset berdasarkan nilai indeks yang duplikat

dogs_ind2.loc["Labrador"]

           name  color  height_cm  weight_kg
breed                                       
Labrador  Bella  Brown         56         25
Labrador    Max  Black         59         29

Indeks berjenjang, juga dikenal sebagai indeks hierarkis

dogs_ind3 = dogs.set_index(["breed", "color"])
print(dogs_ind3)

                      name  height_cm  weight_kg
breed       color                               
Labrador    Brown    Bella         56         25
Poodle      Black  Charlie         43         23
Chow Chow   Brown     Lucy         46         22
Schnauzer   Grey    Cooper         49         17
Labrador    Black      Max         59         29
Chihuahua   Tan     Stella         18          2
St. Bernard White   Bernie         77         74

Melakukan subset pada tingkat luar dengan daftar

dogs_ind3.loc[["Labrador", "Chihuahua"]]

                   name  height_cm  weight_kg
breed     color                              
Labrador  Brown   Bella         56         25
          Black     Max         59         29
Chihuahua Tan    Stella         18          2

Melakukan subset pada tingkat dalam dengan daftar tuple

dogs_ind3.loc[[("Labrador", "Brown"), ("Chihuahua", "Tan")]]

                   name  height_cm  weight_kg
breed     color                              
Labrador  Brown   Bella         56         25
Chihuahua Tan    Stella         18          2

Mengurutkan berdasarkan nilai indeks

dogs_ind3.sort_index()

                      name  height_cm  weight_kg
breed       color                               
Chihuahua   Tan     Stella         18          2
Chow Chow   Brown     Lucy         46         22
Labrador    Black      Max         59         29
            Brown    Bella         56         25
Poodle      Black  Charlie         43         23
Schnauzer   Grey    Cooper         49         17
St. Bernard White   Bernie         77         74

Mengontrol sort_index

dogs_ind3.sort_index(level=["color", "breed"], ascending=[True, False])

                      name  height_cm  weight_kg
breed       color                               
Poodle      Black  Charlie         43         23
Labrador    Black      Max         59         29
            Brown    Bella         56         25
Chow Chow   Brown     Lucy         46         22
Schanuzer   Grey    Cooper         49         17
Chihuahua   Tan     Stella         18          2
St. Bernard White   Bernie         77         74

Sekarang Anda memiliki dua masalah.

Nilai indeks adalah hanya data.
Pengindeksan melanggar prinsip "data yang rapi"
Anda perlu mempelajari dua sintaks.

kumpulan data temperatur

	Tanggal:	kota	Negara	avg_temp_c
0	01-01-2000	Abidjan	Pantai Gading	27.293
1	2000-02-01	Abidjan	Pantai Gading	27.685
2	01-03-2000	Abidjan	Pantai Gading	29.061
3	01-04-2000	Abidjan	Pantai Gading	28.162
4	01-05- 2000	Abidjan	Pantai Gading	27.547

Ayo berlatih!

Manipulasi Data dengan pandas