目录
- 前言
- 正文
- 将现有数据转换为 ndarray
- list转ndarray
- 改变默认类型
- tuple 转 ndarray
- list of tuples 转 ndarray
- numpy.frombuffer
- 迭代器 iterator 转 ndarray
前言
最近在看 [Numpy文档][1] 和 [tutorialspoint Numpy Tutorial][2] 时,发现了一下之前没用过的ndarray高级用法,加上我之前知道的方法,总结一下。以后会陆续更新。
正文
将现有数据转换为 ndarray
使用 numpy.asarray 进行转换 :
numpy.asarray(a, dtype = None, order = None)
list转ndarray
''' list '''
import numpy as np
x = [1,2,3]
a = np.asarray(x)
print(a)
# 输出:
[1 2 3]
改变默认类型
import numpy as np
x = [1,2,3]
a = np.asarray(x, dtype = float)
print(a)
# 输出:
[ 1. 2. 3.]
tuple 转 ndarray
x = (1,2,3)
a = np.asarray(x)
print(a)
# 输出:
[1 2 3]
list of tuples 转 ndarray
import numpy as np
x = [(1,2,3),(4,5)]
a = np.asarray(x)
print(a)
# 输出:
[(1, 2, 3) (4, 5)]
numpy.frombuffer
import numpy as np
s = 'Hello World'
a = np.frombuffer(s, dtype = 'S1')
print(a)
# 输出:
['H' 'e' 'l' 'l' 'o' ' ' 'W' 'o' 'r' 'l' 'd']
迭代器 iterator 转 ndarray
import numpy as np
list = range(5)
it = iter(list)
# use iterator to create ndarray
x = np.fromiter(it, dtype = float)
print(x)
# 输出:
[0. 1. 2. 3. 4.]
参考网页 : https://www.tutorialspoint.com/numpy/numpy_array_from_existing_data.htm
[1]: https://docs.scipy.org/doc/
[2]: https://www.tutorialspoint.com/numpy/index.htm