python中pow函数用法_Python pow()用法及代码示例

Python提供了计算数字幂的功能，因此可以简化计算数字幂的任务。它在日常编程中具有许多应用程序。

天真的计算能力的方法：

# Python code to demonstrate naive method

# to compute power

n = 1

for i in range(1,5):

n=3*n

print ("The value of 3**4 is:",end="")

print (n)

输出：

The value of 3**4 is:81

使用pow()

1. float pow(x，y)：此函数计算x ** y。此函数首先将其参数转换为float，然后计算幂。

Declaration:

float pow(x,y)

参数：

x: Number whose power has to be calculated.

y: Value raised to compute power.

返回值：

Returns the value x**y in float.

# 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

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

Declaration:

float pow(x,y,mod)

参数：

x: Number whose power has to be calculated.

y: Value raised to compute power.

mod: Value with which modulus has to be computed.

返回值：

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

# 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：

# 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