In Python, variables can store different types of data, such as integers, strings, or floating-point numbers. When working with numerical values that have decimal points or require high precision, the double data type is often used. In this tutorial, we will learn how to declare and use double data types in Python.

### Step 1: Understand Python’s Default Data Types

In Python, there is no explicit double data type like in other languages such as C++ or Java. Instead, Python provides the **float** data type to represent floating-point numbers, including integers and decimals.

The **float** data type is already implemented as a double-precision floating-point number in most Python implementations, including CPython, which is the most common Python implementation.

### Step 2: Declare a Variable with Double Data Type

To declare a variable with a double data type, simply assign a floating-point number to the variable. You can do this by appending a decimal point to the number or using scientific notation with an “e” or “E”. Python will automatically store the value as a double. Here’s an example:

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my_double = 3.14 |

Now, the variable `my_double`

contains a double value of 3.14.

### Step 3: Working with Double Variables

You can perform various mathematical operations with double variables just like with any other numeric data type. For example:

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a = 10.0 b = 20.5 # Addition c = a + b print("a + b = ", c) |

**Output**

a + b = 30.5

Keep in mind that floating-point arithmetic can sometimes produce unexpected results due to limited precision. You can use the **decimal** module to perform arithmetic with higher precision.

### Step 4: Converting Other Data Types to Double

To convert an **integer** or a **string** to a double, use the **float()** function:

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# Converting an integer to a double integer_value = 42 double_value = float(integer_value) print(double_value) # Converting a string to a double string_value = "3.14" double_value = float(string_value) print(double_value) |

**Output**

42.0 3.14

Keep in mind that if you attempt to convert a string with an invalid numeric format, you will get a `ValueError`

.

## Full Example

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a = 10.0 b = 20.5 # Addition c = a + b print("a + b = ", c) # Converting an integer to a double integer_value = 42 double_value = float(integer_value) print(double_value) # Converting a string to a double string_value = "3.14" double_value = float(string_value) print(double_value) |

## Output

a + b = 30.5 42.0 3.14

## Conclusion

In this tutorial, we learned that Python does not have a dedicated double data type. Instead, the **float** data type is used to store double-precision floating-point numbers. We demonstrated how to declare double variables, perform arithmetic operations with them, and convert other data types to doubles.

Remember to consider the limited precision of floating-point arithmetic and use the **decimal** module if higher precision is required.