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...
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':...
array([5,2,6,2,7,5,6,8,2,9]) print ('第一个数组:') print (a) print ('\n') print ('第一个数组的去重值:') u = np.unique(a) print (u) print ('\n') print ('去重数组的索引数组:') u,indices = np.unique(a, return_index = True) print (indices) print ('\n') ...
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...
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...
2. 高效 Index 不需要循环 3. 非常高效快速媲美C的速度 Array 的创建和访问 import numpy as np 1. 使用python的list创建数组 list1 = [1,2,3,4] array= np.array( list1 ) 2. 创建二维数组 list1 = [1,2,3,4] list2 = [5,6,7,8] ...
'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...
import numpy as nparr = np.array([1, 2, 3, 4])print(arr[2] + arr[3]) Try it Yourself » Access 2-D ArraysTo access elements from 2-D arrays we can use comma separated integers representing the dimension and the index of the element.Think...
array([1, 2, 3]) >>> c = np.array([1.0, 2, 4]) >>> a[c] Traceback (most recent call last): File "<pyshell#51>", line 1, in <module> a[c] IndexError: arrays used as indices must be of integer (or boolean) type ...
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 ...