[英]Split 2D NumPy array of strings on “,” character
I have a 2D NumPy of strings array like: a = array([['1,2,3'], ['3,4,5']], dtype=object)
and I would like to convert it into a 2D Numpy array like this: a = array([['1','2','3'], ['4','5','6']])
.我有一个 2D NumPy 字符串数组,例如:
a = array([['1,2,3'], ['3,4,5']], dtype=object)
我想将它转换为 2D像这样的 Numpy 数组: a = array([['1','2','3'], ['4','5','6']])
。 I would then like to also convert the strings to floats, so the final array would look like this: a = array([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]])
.然后,我还想将字符串转换为浮点数,因此最终数组将如下所示:
a = array([[1.0, 2.0, 3.0], [4.0, 5.0, 6.0]])
。 Any help is greatly appreciated.任何帮助是极大的赞赏。
Since it's an object array, we might as well iterate and use plain python split:由于它是一个对象数组,我们不妨迭代并使用普通的python拆分:
In [118]: a = np.array([['1,2,3'], ['3,4,5']], dtype=object)
In [119]: a.shape
Out[119]: (2, 1)
In [120]: np.array([x.split(',') for x in a.ravel()])
Out[120]:
array([['1', '2', '3'],
['3', '4', '5']], dtype='<U1')
In [122]: np.array([x.split(',') for x in a.ravel()],dtype=float)
Out[122]:
array([[1., 2., 3.],
[3., 4., 5.]])
I raveled it to simplify iteration.我用它来简化迭代。 Plus the result doesn't need that 2nd size 1 dimension.
此外,结果不需要第二个尺寸 1 维。
There is a np.char
function that applies split
to elements of an array, but the result is messier:有一个
np.char
函数将split
应用于数组的元素,但结果更混乱:
In [129]: a.astype(str)
Out[129]:
array([['1,2,3'],
['3,4,5']], dtype='<U5')
In [130]: np.char.split(_, sep=',')
Out[130]:
array([[list(['1', '2', '3'])],
[list(['3', '4', '5'])]], dtype=object)
In [138]: np.stack(Out[130].ravel()).astype(float)
Out[138]:
array([[1., 2., 3.],
[3., 4., 5.]])
Another way:其它的办法:
In [132]: f = np.frompyfunc(lambda astr: np.array(astr.split(','),float),1,1)
In [133]: f(a)
Out[133]:
array([[array([1., 2., 3.])],
[array([3., 4., 5.])]], dtype=object)
In [136]: np.stack(_.ravel())
Out[136]:
array([[1., 2., 3.],
[3., 4., 5.]])
Iterate through rows and use split(',')
to split each row at the commas, and put the result in a new numpy array with a numeric data type:遍历行并使用
split(',')
在逗号处拆分每一行,并将结果放入具有数字数据类型的新 numpy 数组中:
import numpy as np
a = np.array([['1,2,3'], ['3,4,5']])
b = np.array([x[0].split(',') for x in a], dtype=np.float32)
print(b)
#[[ 1. 2. 3.]
# [ 3. 4. 5.]]
I would like to propose this if you don't mind having them as a vector如果您不介意将它们作为载体,我想提出这个建议
np.array([["asa,asd"], ["dasd,asdaf,asfasf"]], dtype=object)
Out[31]:
array([['asa,asd'],
['dasd,asdaf,asfasf']], dtype=object)
np.concatenate(np.char.split(Out[31].astype(str), ",").ravel())
Out[32]: array(['asa', 'asd', 'dasd', 'asdaf', 'asfasf'], dtype='<U6')
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