Numpy數組創建

import numpy as np
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numpy中的ndarray數組
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ary = np.array([1, 2, 3, 4, 5])
print(ary)
ary = ary * 10
print(ary)

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ndarray對象的創建
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# 創建二維數組
# np.array([[],[],...])
a = np.array([[1, 2, 3, 4], [5, 6, 7, 8]])
print(a)

# np.arange(起始值, 結束值, 步長（默認1）)
b = np.arange(1, 10, 1)
print(b)

# np.zeros(數組元素個數, dtype=‘數組元素類型‘)
 

c = np.zeros(10)
print(c, ‘; c.dtype:‘, c.dtype)

# np.ones(數組元素個數, dtype=‘數組元素類型‘)
d = np.ones(10, dtype=‘int64‘)
print(d, ‘; d.dtype:‘, d.dtype)

Numpy的ndarray對象屬性：

數組的維度：array.shape

元素的類型：array.dtype

數組元素的個數：array.size

數組的索引（下標）:array[0]

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數組的基本屬性
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a = np.array([[1, 2, 3], [4, 5, 6]])
print
 
(a)

# 測試數組的基本屬性
print(‘a.shape:‘, a.shape)
# a.shape = (6, )  # 此格式可將原數組結構變成1行6列的數據結構
# print(a, ‘a.shape:‘, a.shape)
print(‘a.size:‘, a.size)
print(‘len(a):‘, len(a))

# 數組元素的索引
ary = np.arange(1, 28)
ary.shape = (3, 3, 3)   # 創建三維數組
print(ary, ‘; ary.shape:‘, ary.shape)

print(‘ary[0]:‘, ary[0])
print
 
(‘ary[0][0]:‘, ary[0][0])
print(‘ary[0][0][0]:‘, ary[0][0][0])
print(‘ary[0,0,0]:‘, ary[0, 0, 0])

# 遍歷三維數組
for i in range(ary.shape[0]):
    for j in range(ary.shape[1]):
        for k in range(ary.shape[2]):
            print(ary[i, j, k], end=‘ ‘)

Numpy：數組創建、數組基本屬性