{"id":4665,"date":"2022-09-10T03:14:06","date_gmt":"2022-09-10T03:14:06","guid":{"rendered":"https:\/\/www.pythontutorial.net\/?page_id=4665"},"modified":"2022-09-10T04:12:21","modified_gmt":"2022-09-10T04:12:21","slug":"python-float","status":"publish","type":"page","link":"https:\/\/www.pythontutorial.net\/python-built-in-functions\/python-float\/","title":{"rendered":"Python float()"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you’ll learn how to use Python float()<\/code> to convert a number or a string to a floating point number.<\/p>\n\n\n\n

Introduction to the Python float() #<\/a><\/h2>\n\n\n\n

The float()<\/code> accepts a string or an number, either an integer or a floating-point number, and converts it to a floating-point number<\/a>, if possible:<\/p>\n\n\n

float(x)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
If x<\/code> is a string, it should contain a decimal number. Also, it can have an optional sign like a minus (-<\/code>) or plus (+<\/code>).<\/p>\n\n\n\n
If x<\/code> is an integer or a floating point number, the float()<\/code><\/code> returns the same floating point number with the same value. If the value is outside the range of a Python float, the float()<\/code><\/code> will raise an OverflowError<\/code>.<\/p>\n\n\n\n
If x is an object, the float()<\/code><\/code> delegates to the x.__float<\/code><\/code>__()<\/code> method. If the object x does not have the __float__()<\/code> method, the float()<\/code><\/code> will use the __index__()<\/code> method.<\/p>\n\n\n\n
The x<\/code> parameter is optional. If you omit it, the float()<\/code> will return 0.0<\/code>.<\/p>\n\n\n\n
Python float() examples #<\/a><\/h2>\n\n\n\n
Let’s take some examples of using the Python float()<\/code>.<\/p>\n\n\n\n
\"Python<\/figure>\n\n\n\n
1) Using float() to convert a string to a floating point number #<\/a><\/h3>\n\n\n\n
The following example uses the float()<\/code> to convert strings to floating point numbers:<\/p>\n\n\n
f = float('+1.99'<\/span>)\nprint(f)  # ? 1.99<\/span>\n\nf = float('-5.99'<\/span>)\nprint(f)  # ? -5.99<\/span>\n\nf = float('199e-001'<\/span>)\nprint(f)  # ? 19.9<\/span>\n\nf = float('+1E3'<\/span>)\nprint(f)  # ? 1000.0<\/span>\n\nf = float('-Infinity'<\/span>)\nprint(f)  # ? -inf<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
2) Using float() to convert an integer to a floating point number #<\/a><\/h3>\n\n\n\n
The following example uses the float()<\/code> to convert integers to floating point numbers:<\/p>\n\n\n
f = float(10<\/span>)\nprint(f)  # ? 10.0<\/span>\n\nf = float(-20<\/span>)\nprint(f)  # ? -20.0<\/span>\n\nf = float(0<\/span>)\nprint(f)  # ? 0.0<\/span>\n\nf = float()\nprint(f)  # ? 0.0<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
3) Using the Python float() to convert an object to a floating point number #<\/a><\/h3>\n\n\n\n
The following example illustrates how to convert an object to a floating point number:<\/p>\n\n\n
class<\/span> Product<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, name, price)<\/span>:<\/span>\n        self.name = name\n        self.price = price\n\n    def<\/span> __float__<\/span>(self)<\/span>:<\/span>\n        return<\/span> float(self.price)\n\n\nphone = Product('phone'<\/span>, 999<\/span>)\nprint(float(phone))<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Output:<\/p>\n\n\n
999.0<\/span><\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
How it works.<\/p>\n\n\n\n
First, define a class Product that has two attributes name and price. The __float__()<\/code> method returns the floating point number of the price:<\/p>\n\n\n
class<\/span> Product<\/span>:<\/span>\n    def<\/span> __init__<\/span>(self, name, price)<\/span>:<\/span>\n        self.name = name\n        self.price = price\n\n    def<\/span> __float__<\/span>(self)<\/span>:<\/span>\n        return<\/span> float(self.price)<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Second, create a new instance of the product and convert it to a floating point number:<\/p>\n\n\n
phone = Product('phone'<\/span>, 999<\/span>)\nprint(float(phone))<\/code><\/span>Code language:<\/span> Python<\/span> (<\/span>python<\/span>)<\/span><\/small><\/pre>\n\n\n
Summary #<\/a><\/h2>\n\n\n\n
  • Use the Python float()<\/code> to convert a string or an integer to a floating point number.<\/li><\/ul>\n
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