index=np.where(arr==6)[0][0] 1. 这将返回与6相等的第一个元素的索引位置。 代码示例 下面是使用Python NumPy库查找数据索引的完整代码示例: importnumpyasnp arr=np.array([2,4,6,8,10])index=np.where(arr==6)print("Index of number 6:",index)index=np.argwhere(arr==6)print("Index of n...
array([[30,40,70],[80,20,10],[50,90,60]]) print ('我们的数组是:') print (a) print ('\n') print ('调用argmax() 函数:') print (np.argmax(a)) print ('\n') print ('展开数组:') print (a.flatten()) print ('\n') print ('沿轴0 的最大值索引:') maxindex = np....
In the above array, 5 is the 3rd element. However, its index is 2. This is because the array indexing starts from 0, that is, the first element of the array has index 0, the second element has index 1, and so on. Now, we'll see how we can access individual items from the arr...
Generally speaking, what is returned when index arrays are used is an array with the same shape as the index array, but with the type and values of the array being indexed. 以二维数组为例: >>>importnumpyasnp>>>x = np.arange(12).reshape(3,4)>>>x array([[0,1,2,3], [4,5,6...
a=np.array([1,2,3,4,5],dtype=np.int32) #创建数组时,每一个元素的“ 类型 ”都是相同的, 也就是说,如果要创建类似于上面的“ 结构体数组 ”,第一件事情是需要定义一个全新的dtype。参见下面的代码: import numpy as npstudent_type={'names':('name', 'age', 'sex','weight'), 'formats'...
arr=np.array([[ 1,2,3],[4,5,6],[7,8,9]])# 获取(0,1)、(1,2)和( 2,0)位置的元素print(arr[[0,1,2],[1,2,0]])# 输出:[2 6 7] 注意事项 NumPy索引是从0开始的。 切片是原数组的视图,修改切片会影响原数组。如果需要复制,可以使用.copy()方法。
array([7,7,9,2]) 当然,类似切片那样,Index也可以使用负数。但是索引值不能越界! 1 2 >>> x[np.array([3,3,-3,8])] array([7,7,4,2]) 三、索引多维数组 例1:产生一个5X7的数组,选择0,2,4行,0,1,2列的数 1 2 3 >>> y=np.arange(35).reshape(5,7) ...
In this example, index or ind, was defined as alist,but we could also have defined that as a NumPy array. 在本例中,index或ind被定义为Python列表,但我们也可以将其定义为NumPy数组。 So I can take my previous list, 0, 2, 3, turn that into a NumPy array,and I can still do my inde...
index3isoutofboundsforaxis0withsize3>>># same as `a[i, j]`>>>a[tuple(s)]array([[2,5...
'nanmedian', 'nanmin', 'nanpercentile', 'nanprod', 'nanstd', 'nansum', 'nanvar', 'nbytes', 'ndarray', 'ndenumerate', 'ndfromtxt', 'ndim', 'ndindex', 'nditer', 'negative', 'nested_iters', 'newaxis', 'nextafter', 'nonzero', 'not_equal', 'nper', 'npv', 'numarray', 'num...