[英]How to assign a string value to an array in numpy?
When I try to assign a string to an array like this: 当我尝试将字符串分配给这样的数组时:
CoverageACol[0,0] = "Hello"
I get the following error 我收到以下错误
Traceback (most recent call last):
File "<pyshell#19>", line 1, in <module>
CoverageACol[0,0] = "hello"
ValueError: setting an array element with a sequence.
However, assigning an integer does not result in an error: 但是,分配整数不会导致错误:
CoverageACol[0,0] = 42
CoverageACol is a numpy array. CoverageACol是一个numpy数组。
Please help! 请帮忙! Thanks! 谢谢!
You get the error because NumPy's array is homogeneous, meaning it is a multidimensional table of elements all of the same type . 你得到错误是因为NumPy的数组是同构的,这意味着它是一个多维表格的所有相同类型的元素 。 This is different from a multidimensional list-of-lists in "regular" Python, where you can have objects of different type in a list. 这与“常规”Python中的多维列表列表不同,您可以在列表中包含不同类型的对象。
Regular Python: 常规Python:
>>> CoverageACol = [[0, 1, 2, 3, 4],
[5, 6, 7, 8, 9]]
>>> CoverageACol[0][0] = "hello"
>>> CoverageACol
[['hello', 1, 2, 3, 4],
[5, 6, 7, 8, 9]]
NumPy: NumPy的:
>>> from numpy import *
>>> CoverageACol = arange(10).reshape(2,5)
>>> CoverageACol
array([[0, 1, 2, 3, 4],
[5, 6, 7, 8, 9]])
>>> CoverageACol[0,0] = "Hello"
---------------------------------------------------------------------------
ValueError Traceback (most recent call last)
/home/biogeek/<ipython console> in <module>()
ValueError: setting an array element with a sequence.
So, it depends on what you want to achieve, why do you want to store a string in an array filled for the rest with numbers? 那么,这取决于你想要实现的目标,为什么你要将一个字符串存储在一个数组中? If that really is what you want, you can set the datatype of the NumPy array to string: 如果这真的是你想要的,你可以将NumPy数组的数据类型设置为string:
>>> CoverageACol = array(range(10), dtype=str).reshape(2,5)
>>> CoverageACol
array([['0', '1', '2', '3', '4'],
['5', '6', '7', '8', '9']],
dtype='|S1')
>>> CoverageACol[0,0] = "Hello"
>>> CoverageACol
array([['H', '1', '2', '3', '4'],
['5', '6', '7', '8', '9']],
dtype='|S1')
Notice that only the first letter of Hello
gets assigned. 请注意,只分配Hello
的第一个字母。 If you want the whole word to get assigned, you need to set an array-protocol type string : 如果要分配整个单词,则需要设置数组协议类型字符串 :
>>> CoverageACol = array(range(10), dtype='a5').reshape(2,5)
>>> CoverageACol:
array([['0', '1', '2', '3', '4'],
['5', '6', '7', '8', '9']],
dtype='|S5')
>>> CoverageACol[0,0] = "Hello"
>>> CoverageACol
array([['Hello', '1', '2', '3', '4'],
['5', '6', '7', '8', '9']],
dtype='|S5')
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