Utility Functions For Hexadecimal Strings

Table of Contents

Introduction

Hexadecimal strings specific utility functions used in this specification.

`has_hex_prefix`	Check if a hex string starts with hex prefix (0x).
`remove_hex_prefix`	Remove 0x prefix from a hex string if present. This function returns the
`hex_to_bytes`	Convert hex string to bytes.
`hex_to_bytes8`	Convert hex string to 8 bytes.
`hex_to_bytes32`	Convert hex string to 32 bytes.
`hex_to_bytes256`	Convert hex string to 256 bytes.
`hex_to_hash`	Convert hex string to hash32 (32 bytes).
`hex_to_uint`	Convert hex string to Uint.
`hex_to_u64`	Convert hex string to Uint64.
`hex_to_u256`	Convert hex string to U256.

has_hex_prefix(hex_string: str) → bool

Check if a hex string starts with hex prefix (0x).

Parameters: hex_string – The hexadecimal string to be checked for presence of prefix.
Returns: has_prefix – Boolean indicating whether the hex string has 0x prefix.
Return type: bool

def has_hex_prefix(hex_string: str) -> bool:
    return hex_string.startswith("0x")

remove_hex_prefix(hex_string: str) → str

Remove 0x prefix from a hex string if present. This function returns the passed hex string if it isn’t prefixed with 0x.

Parameters: hex_string – The hexadecimal string whose prefix is to be removed.
Returns: modified_hex_string – The hexadecimal string with the 0x prefix removed if present.
Return type: str

def remove_hex_prefix(hex_string: str) -> str:
    if has_hex_prefix(hex_string):
        return hex_string[len("0x") :]

    return hex_string

hex_to_bytes(hex_string: str) → ethereum.base_types.Bytes 

Convert hex string to bytes.

Parameters: hex_string – The hexadecimal string to be converted to bytes.
Returns: byte_stream – Byte stream corresponding to the given hexadecimal string.
Return type: bytes

def hex_to_bytes(hex_string: str) -> Bytes:
    return bytes.fromhex(remove_hex_prefix(hex_string))

hex_to_bytes8(hex_string: str) → ethereum.base_types.Bytes8 

Convert hex string to 8 bytes.

Parameters: hex_string – The hexadecimal string to be converted to 8 bytes.
Returns: 8_byte_stream – 8-byte stream corresponding to the given hexadecimal string.
Return type: bytes

def hex_to_bytes8(hex_string: str) -> Bytes8:
    return Bytes8(bytes.fromhex(remove_hex_prefix(hex_string).rjust(16, "0")))

hex_to_bytes32(hex_string: str) → ethereum.base_types.Bytes32 

Convert hex string to 32 bytes.

Parameters: hex_string – The hexadecimal string to be converted to 32 bytes.
Returns: 32_byte_stream – 32-byte stream corresponding to the given hexadecimal string.
Return type: bytes

def hex_to_bytes32(hex_string: str) -> Bytes32:
    return Bytes32(bytes.fromhex(remove_hex_prefix(hex_string).rjust(64, "0")))

hex_to_bytes256(hex_string: str) → ethereum.base_types.Bytes256 

Convert hex string to 256 bytes.

Parameters: hex_string – The hexadecimal string to be converted to 256 bytes.
Returns: 256_byte_stream – 256-byte stream corresponding to the given hexadecimal string.
Return type: bytes

def hex_to_bytes256(hex_string: str) -> Bytes256:
    return Bytes256(
        bytes.fromhex(remove_hex_prefix(hex_string).rjust(512, "0"))
    )

hex_to_hash(hex_string: str) → ethereum.crypto.hash.Hash32 

Convert hex string to hash32 (32 bytes).

Parameters: hex_string – The hexadecimal string to be converted to hash32.
Returns: hash – 32-byte stream obtained from the given hexadecimal string.
Return type: Hash32

def hex_to_hash(hex_string: str) -> Hash32:
    return Hash32(bytes.fromhex(remove_hex_prefix(hex_string)))

hex_to_uint(hex_string: str) → ethereum.base_types.Uint 

Convert hex string to Uint.

Parameters: hex_string – The hexadecimal string to be converted to Uint.
Returns: converted – The unsigned integer obtained from the given hexadecimal string.
Return type: Uint

def hex_to_uint(hex_string: str) -> Uint:
    return Uint(int(remove_hex_prefix(hex_string), 16))

hex_to_u64(hex_string: str) → ethereum.base_types.Uint64 

Convert hex string to Uint64.

Parameters: hex_string – The hexadecimal string to be converted to U256.
Returns: converted – The Uint64 integer obtained from the given hexadecimal string.
Return type: Uint64

def hex_to_u64(hex_string: str) -> Uint64:
    return Uint64(int(remove_hex_prefix(hex_string), 16))

hex_to_u256(hex_string: str) → ethereum.base_types.U256 

Convert hex string to U256.

Parameters: hex_string – The hexadecimal string to be converted to U256.
Returns: converted – The U256 integer obtained from the given hexadecimal string.
Return type: U256

def hex_to_u256(hex_string: str) -> U256:
    return U256(int(remove_hex_prefix(hex_string), 16))