二維陣列
Python 金融入門
Adina Howe
Professor
二維陣列
import numpy as np
months = [1, 2, 3]
prices = [238.11, 237.81, 238.91]
cpi_array = np.array([months, prices])
print(cpi_array)
[[ 1. 2. 3. ]
[ 238.11 237.81 238.91]]
陣列方法
print(cpi_array)
[[ 1. 2. 3. ]
[ 238.11 237.81 238.91]]
「.shape」會回傳陣列的維度
print(cpi_array.shape)
(2, 3)
「.size」會回傳陣列的總元素數
print(cpi_array.size)
6
陣列函式
import numpy as np
prices = [238.11, 237.81, 238.91]
prices_array = np.array(prices)
「np.mean()」計算輸入的平均值
print(np.mean(prices_array))
238.27666666666667
「np.std()」計算輸入的標準差
print(np.std(prices_array))
0.46427960923946671
`arange()` 函式
numpy.arange() 會依起點、終點、步長建立陣列
import numpy as np months = np.arange(1, 13)print(months)
[ 1 2 3 4 5 6 7 8 9 10 11 12]
months_odd = np.arange(1, 13, 2)print(months_odd)
[ 1 3 5 7 9 11]
`transpose()` 函式
numpy.transpose() 會對 numpy 陣列進行列、欄互換
print(cpi_array)
[[ 1. 2. 3. ]
[ 238.11 237.81 238.91]]
cpi_transposed = np.transpose(cpi_array)
print(cpi_transposed)
[[ 1. 238.11]
[ 2. 237.81]
[ 3. 238.91]]
二維陣列的索引
print(cpi_array)
[[ 1. 2. 3. ]
[ 238.11 237.81 238.91]]
# row index 1, column index 2
cpi_array[1, 2]
238.91
# all row slice, third column
print(cpi_array[:, 2])
[ 3. 238.91]
一起來練習吧！
Python 金融入門
