Python中的 pow()

Python pow()函数返回给定数字的幂。此函数计算 x**y 。此函数首先将其参数转换为浮点数，然后计算幂。

Syntax: pow(x,y)

Parameters : 

• x : Number whose power has to be calculated.
• y : Value raised to compute power.

Return Value :  Returns the value x**y in float.

Python pow() 示例

示例 1：pow() 的工作

Python3

# Python code to demonstrate pow()
# version 1
 
print("The value of 3**4 is : ", end="")
 
# Returns 81
print(pow(3, 4))

输出：

The value of 3**4 is : 81.0

示例 2：具有三个参数的Python pow()

float pow(x,y,mod)函数计算 (x**y) % mod 。此函数首先将其参数转换为浮点数，然后计算幂。

Syntax: float pow(x,y,mod)

Parameters : 

• x : Number whose power has to be calculated.
• y : Value raised to compute power.
• mod :  Value with which modulus has to be computed.

Return Value :  Returns the value (x**y) % mod in float.

Python3

# Python code to demonstrate pow()
# version 2
 
print("The value of (3**4) % 10 is : ", end="")
 
# Returns 81%10
# Returns 1
print(pow(3, 4, 10))

输出：

The value of (3**4) % 10 is : 1

pow() 中的实现案例：

Python3

# Python code to discuss negative
# and non-negative cases
 
# positive x, positive y (x**y)
print("Positive x and positive y : ", end="")
print(pow(4, 3))
 
print("Negative x and positive y : ", end="")
# negative x, positive y (-x**y)
print(pow(-4, 3))
 
print("Positive x and negative y : ", end="")
# positive x, negative y (x**-y)
print(pow(4, -3))
 
print("Negative x and negative y : ", end="")
# negative x, negative y (-x**-y)
print(pow(-4, -3))

输出：

Positive x and positive y : 64
Negative x and positive y : -64
Positive x and negative y : 0.015625
Negative x and negative y : -0.015625