Python float.fromhex Usage Detailed Explanation and Examples

Python’s float.fromhex method is used to convert a hexadecimal floating-point number to an actual floating-point number. Its syntax is as follows:

float.fromhex(s)

Where, s is a string representing a hexadecimal floating-point number. This string must follow a specific format:

• The first character must be a plus or minus sign (optional).
• The next character must be '0x' or '0X', indicating a hexadecimal number.
• Subsequent characters must be 0 through 9, a through f, or A through F, indicating a hexadecimal digit.
• If any characters in the string are not hexadecimal digits, a ValueError exception is raised.

Here are some examples using the float.fromhex method:

Example 1:

s = '0x1.6p10'
result = float.fromhex(s)
print(result) # Output: 3840.0

In this example, the string '0x1.6p10' represents the hexadecimal floating-point number 1.6 * 2^10, which is the decimal value 3840.0.

Example 2:

s = '-0x3.b2p-4'
result = float.fromhex(s)
print(result) # Output: -0.9404296875

In this example, the string '-0x3.b2p-4' represents the hexadecimal floating-point number -3.b2 * 2^(-4), which is the decimal value -0.9404296875.

Example 3:

s = '0x1p-1074'
result = float.fromhex(s)
print(result) # Output: 5e-324

In this example, the string '0x1p-1074' represents the hexadecimal floating-point number 1 * 2^(-1074), which is the decimal value 5e-324. This is the smallest positive non-zero floating-point number specified in the IEEE 754 standard.

In these examples, the float.fromhex method converts the hexadecimal floating-point number represented by the string to an actual floating-point number and returns the result. Note that the returned floating-point number is still of type float.