We will index an array C in the following example by using a Boolean mask. It is called fancy indexing, if arrays are indexed by using boolean or integer arrays (masks). The result will be a copy and not a view. In our next example, we will use the Boolean mask of one array to ...
array([4, 5]) boolean index index还可以使用boolean值,表示是否选择这一个index的数据。 我们先看下怎么构建一个boolean类型的数组: names = np.array(['Bob', 'Joe', 'Will', 'Bob', 'Will', 'Joe', 'Joe']) names == 'Bob' array([ True, False, False, True, False, False, False]) 上...
An array of booleans is returned. >>> from numpy import * >>> a = array([3,6,8,9]) >>> a == 6 array([False, True, False, False], dtype=bool) >>> a >= 7 array([False, False, True, True], dtype=bool) >>> a < 5 array([ True, False, False, False], dtype=bool...
We then use this boolean mask to indexarray1, which returns a flattened 1D array containing only the elements that satisfy the condition. [14,19,21,25,29,35]
索引:获取特定元素,arr[index],是copy 布尔索引:用布尔 (boolean) 类型值数组来进行索引,是copy 花式索引:用索引数组进行索引,是copy 切片:截取一段元素,arr[start:stop:step],是view 比如: arr=np.arange(10)# 索引 indexingprint("Array value with index 0: {}".format(arr[0]))# Array value with ...
Out[3]: array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9]) #获取索引值为0的元素 In [4]: x[0] Out[4]: 0 #获取索引值为2的元素 In [5]: x[2] Out[5]: 2 #获取前5个元素 In [6]: x[:5] Out[6]: array([0, 1, 2, 3, 4]) ...
array([[2, 3], [5, 6]]) 代码语言:javascript 复制 arr2d[1, :2] 代码语言:javascript 复制 array([4, 5]) boolean index index还可以使用boolean值,表示是否选择这一个index的数据。 我们先看下怎么构建一个boolean类型的数组: 代码语言:javascript 复制 names = np.array(['Bob', 'Joe', '...
Boolean array indexing This advanced indexing occurs when obj is an array object of Boolean type, such as may be returned from comparison operators. 布尔型索引发生的条件是obj是一个布尔型数组,比如可以从比较运算符返回。 其实这个布尔型索引和整数列表的高级索引是相似的。
[Python] Boolean Or "Mask" Index Arrays filter with numpy,NumPyReference: IndexingIntegerarrayindexingBooleanarrayindexingNote:Theexpression a<mean producesabooleanarray,like:
order : {'C', 'F', 'A'}, optional Read the elements of `a` using this index order, and place the elements into the reshaped array using this index order. 'C' means to read / write the elements using C-like index order, with the last axis index changing fastest, back to the ...