NumPy

Pengantar Python

Hugo Bowne-Anderson

Data Scientist at DataCamp

Ringkasan Daftar

  • Sangat Efektif

  • Kumpulan nilai

  • Menyimpan berbagai tipe

  • Mengubah, menambah, menghapus

  • Kebutuhan akan Ilmu Data

    • Operasi matematika pada kumpulan

    • Kecepatan

Pengantar Python

Ilustrasi

height = [1.73, 1.68, 1.71, 1.89, 1.79]
height
[1.73, 1.68, 1.71, 1.89, 1.79]
weight = [65.4, 59.2, 63.6, 88.4, 68.7]
weight
[65.4, 59.2, 63.6, 88.4, 68.7]
weight / height ** 2
TypeError: unsupported operand type(s) for ** or pow(): 'list' and 'int'
Pengantar Python

Solusi: NumPy

  • Python Numerik

  • Alternatif untuk Daftar Python: Array NumPy

  • Perhitungan pada seluruh array

  • Mudah dan Cepat

  • Penginstalan

    • Di terminal: pip3 install numpy
Pengantar Python

NumPy

import numpy as np

np_height = np.array(height) np_height
array([1.73, 1.68, 1.71, 1.89, 1.79])
np_weight = np.array(weight)
np_weight
array([65.4, 59.2, 63.6, 88.4, 68.7])
bmi = np_weight / np_height ** 2
bmi
array([21.85171573, 20.97505669, 21.75028214, 24.7473475 , 21.44127836])
Pengantar Python

Perbandingan

height = [1.73, 1.68, 1.71, 1.89, 1.79]
weight = [65.4, 59.2, 63.6, 88.4, 68.7]
weight / height ** 2
TypeError: unsupported operand type(s) for ** or pow(): 'list' and 'int'
np_height = np.array(height)
np_weight = np.array(weight)
np_weight / np_height ** 2
array([21.85171573, 20.97505669, 21.75028214, 24.7473475 , 21.44127836])
Pengantar Python

NumPy: komentar

np.array([1.0, "is", True])
array(['1.0', 'is', 'True'], dtype='<U32')
  • Array NumPy: hanya berisi satu jenis
Pengantar Python

NumPy: komentar

python_list = [1, 2, 3]
numpy_array = np.array([1, 2, 3])
python_list + python_list
[1, 2, 3, 1, 2, 3]
numpy_array + numpy_array
array([2, 4, 6])
  • Jenis yang berbeda: perilaku yang berbeda!
Pengantar Python

Subsetting NumPy

bmi
array([21.85171573, 20.97505669, 21.75028214, 24.7473475 , 21.44127836])
bmi[1]
20.975
bmi > 23
array([False, False, False,  True, False])
bmi[bmi > 23]
array([24.7473475])
Pengantar Python

Ayo berlatih!

Pengantar Python

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