计算NumPy掩码数组中连续元素之间的差值
要计算掩码数组中连续元素之间的差值,请在Python NumPy中使用**MaskedArray.ediff1d()**方法。此函数等效于numpy.ediff1d,它考虑了掩码值,详情请参见numpy.ediff1d。
掩码数组是标准numpy.ndarray和掩码的组合。掩码可以是nomask(表示关联数组的任何值均有效)或布尔数组,它确定关联数组的每个元素的值是否有效。
步骤
首先,导入所需的库:
import numpy as np
使用numpy.array()方法创建一个包含整数元素的数组:
arr = np.array([[65, 68, 81], [93, 33, 76], [73, 88, 51], [62, 45, 67]])
print("Array...
", arr)创建一个掩码数组,并将其中一些标记为无效:
maskArr = ma.masked_array(arr, mask =[[1, 0, 0], [ 0, 0, 0], [0, 1, 0], [0, 0, 0]])
print("
Our Masked Array...
", maskArr)获取掩码数组的类型:
print("
Our Masked Array type...
", maskArr.dtype)
获取掩码数组的维度:
print("
Our Masked Array Dimensions...
",maskArr.ndim)获取掩码数组的形状:
print("
Our Masked Array Shape...
",maskArr.shape)
获取掩码数组的元素个数:
print("
Number of elements in the Masked Array...
",maskArr.size)要计算掩码数组中连续元素之间的差值,请在Python NumPy中使用MaskedArray.ediff1d()方法:
print("
Result..
.", np.ediff1d(maskArr))
示例
import numpy as np
import numpy.ma as ma
# Create an array with int elements using the numpy.array() method
arr = np.array([[65, 68, 81], [93, 33, 76], [73, 88, 51], [62, 45, 67]])
print("Array...
", arr)
# Create a masked array and mask some of them as invalid
maskArr = ma.masked_array(arr, mask =[[1, 0, 0], [ 0, 0, 0], [0, 1, 0], [0, 0, 0]])
print("
Our Masked Array...
", maskArr)
# Get the type of the masked array
print("
Our Masked Array type...
", maskArr.dtype)
# Get the dimensions of the Masked Array
print("
Our Masked Array Dimensions...
",maskArr.ndim)
# Get the shape of the Masked Array
print("
Our Masked Array Shape...
",maskArr.shape)
# Get the number of elements of the Masked Array
print("
Number of elements in the Masked Array...
",maskArr.size)
# To compute the differences between consecutive elements of a masked array, use the MaskedArray.ediff1d() method in Python Numpy
print("
Result..
.", np.ediff1d(maskArr))输出
Array... [[65 68 81] [93 33 76] [73 88 51] [62 45 67]] Our Masked Array... [[-- 68 81] [93 33 76] [73 -- 51] [62 45 67]] Our Masked Array type... int64 Our Masked Array Dimensions... 2 Our Masked Array Shape... (4, 3) Number of elements in the Masked Array... 12 Result.. . [-- 13 12 -60 43 -3 -- -- 11 -17 22]
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