Python中的 numpy.all()

numpy.all()函数测试是否所有沿上述轴的数组元素都评估为 True。

Syntax: numpy.all(array,
                    axis = None,
                    out = None,
                    keepdims = class numpy._globals._NoValue at 0x40ba726c)

参数 ：

array    :[array_like]Input array or object whose elements, we need to test.
axis     : [int or tuple of ints, optional]Axis along which array elements 
     are evaluated.
     The default (axis = None) is to perform a logical AND over all the dimensions of the input
     array. Axis may be negative, in which case it counts from the last to the first axis.
out      : [ndarray, optional]Output array with same dimensions as Input array, 
     placed with result
keepdims : [boolean, optional]If this is set to True, the axes which are 
     reduced are left in the result as dimensions with size one. With this option, the result 
     will broadcast correctly against the input array.
     If the default value is passed, then keepdims will not be passed through to the all 
     method of sub-classes of ndarray, however any non-default value will be. If the 
     sub-classes sum method does not implement keepdims any exceptions will be raised.

返回 ：

A new Boolean array as per 'out' parameter

代码 1：

Python

# Python Program illustrating
# numpy.all() method
   
import numpy as geek
   
# Axis = NULL
#  True    False
#  True    True
#  True  : False  =  False
  
print("Bool Value with axis = NONE  : ",
      geek.all([[True,False],[True,True]]))
  
# Axis = 0
#  True    False
#  True    True
#  True  : False
print("\nBool Value with axis = 0  : ",
      geek.all([[True,False],[True,True]], axis = 0))
  
print("\nBool : ", geek.all([-1, 4, 5]))
  
  
# Not a Number (NaN), positive infinity and negative infinity
# evaluate to True because these are not equal to zero.
print("\nBool : ", geek.all([1.0, geek.nan]))
  
print("\nBool Value : ", geek.all([[0, 0],[0, 0]]))

输出 ：

Bool Value with axis = NONE  :  False

Bool Value with axis = 0  :  [ True False]

Bool :  True

Bool :  True

Bool Value :  False

代码 2：

Python

# Python Program illustrating
# numpy.all() method
 
# Parameter : keepdims     
            
import numpy as geek
 
# setting keepdims = True
print("\nBool Value : ", geek.all([[1, 0],[0, 4]], True))
 
 
# setting keepdims = True
print("\nBool Value : ", geek.all([[0, 0],[0, 0]], False))

输出 ：

Bool Value :  [False False]

Bool Value :  [False False]
VisibleDeprecationWarning: using a boolean instead of an integer
 will result in an error in the future
 return umr_all(a, axis, dtype, out, keepdims)

参考： https://docs.scipy.org/doc/numpy-dev/reference/generated/numpy.all.html#numpy.all

注意：这些代码不会在在线 IDE 上运行。因此，请在您的系统上运行它们以探索其工作原理。