Python 如何将字符串转换为数字

要将字符串转换为数字，有多种方法可以使用。让我们一一看看。

使用int()将字符串转换为数字

示例

在这个示例中，我们将使用int()方法将字符串转换为数字 –

# String to be converted
myStr = "200"

# Display the string and it's type
print("String = ",myStr)
print("Type= ", type(myStr))

# Convert the string to integer using int() and display the type
myInt = int(myStr)
print("\nInteger = ", myInt)
print("Type = ", type(myInt))

输出

String =  200
Type=  <class 'str'>

Integer =  200
Type =  <class 'int'>

使用float()将字符串转换为数字

示例

在这个示例中，我们将使用float()方法将字符串转换为浮点数，然后使用int()方法将浮点数转换为整数 –

# String to be converted
myStr = "500"

# Display the string and it's type
print("String = ",myStr)
print("Type= ", type(myStr))

# Convert the string to float
myFloat = float(myStr)
print("\nFloat = ", myFloat)
print("Type = ", type(myFloat))

# Convert the float to int
myInt = int(myFloat)
print("\nInteger = ", myInt)
print("Type = ", type(myInt))

输出

String =  500
Type=  <class 'str'>

Float =  500.0
Type =  <class 'float'>

Integer =  500
Type =  <class 'int'>

将字符串转换为十进制和八进制数

示例

在这个示例中，我们将使用带有基数参数的int()函数将字符串转换为数字。

# String to be converted
myStr = "500"

# Display the string and it's type
print("String = ",myStr)
print("Type= ", type(myStr))

# Convert the string to int
myInt1 = int(myStr)
print("\nInteger (base10) = ", myInt1)
print("Type = ", type(myInt1))

# Convert the string to int
myInt2 = int(myStr, base=8)
print("\nInteger (base8) = ", myInt2)
print("Type = ", type(myInt2))

输出

String =  500
Type=  <class 'str'>
Integer (base10) =  500
Type =  <class 'int'>

Integer (base8) =  320
Type =  <class 'int'>