使用标量赋值
赋值给结构化元素的标量将赋值给所有字段。
标量赋值给结构化数组

import sys
import numpy as np

if __name__ == "__main__":
    if len(sys.argv) < 2:
        n = 2
    else:
        n = int(sys.argv[1])
    print(n)
    T1 = np.dtype([('name', 'S8'), ('salary', 'f4')])
    x = np.zeros(n, dtype=T1)
    print(x)
    x[:] = 3
    print(x)

C:\numpy>python numpy_13.py 5
5
[(b'', 0.) (b'', 0.) (b'', 0.) (b'', 0.) (b'', 0.)]
[(b'3', 3.) (b'3', 3.) (b'3', 3.) (b'3', 3.) (b'3', 3.)]

非结构化数组赋值给结构化数组

import sys
import numpy as np

if __name__ == "__main__":
    if len(sys.argv) < 2:
        n = 2
    else:
        n = int(sys.argv[1])
    print(n)
    T1 = np.dtype([('name', 'S8'), ('salary', 'f4')])
    x = np.zeros(n, dtype=T1)
    print(x)
    r1 = np.arange(n)
    print(r1)
    x[:] = r1
    print(x)

C:\numpy>python numpy_12.py 5
5
[(b'', 0.) (b'', 0.) (b'', 0.) (b'', 0.) (b'', 0.)]
[0 1 2 3 4]
[(b'0', 0.) (b'1', 1.) (b'2', 2.) (b'3', 3.) (b'4', 4.)]

结构化数组也可以赋值给非结构化数组，只要结构化数据类型只有一个字段

import sys
import numpy as np

if __name__ == "__main__":
    T1 = np.dtype([('name', 'S8')])
    x = np.zeros(3, dtype=T1)
    x[0] = ("John")
    x[1] = ("Sam")
    x[2] = ("Johnson")
    print("x type: {0}, val: {1}".format(type(x), x))
    non_struct = np.zeros(3, dtype='S8')
    print("non_struct type: {0}, val: {1}".format(type(non_struct), non_struct))
    non_struct = x
    print("non_struct type: {0}, val: {1}".format(type(non_struct), non_struct))

C:\numpy>python numpy_14.py
x type: <class 'numpy.ndarray'>, val: [(b'John',) (b'Sam',) (b'Johnson',)]
non_struct type: <class 'numpy.ndarray'>, val: [b'' b'' b'']
non_struct type: <class 'numpy.ndarray'>, val: [(b'John',) (b'Sam',) (b'Johnson',)]