Unsigned int to int python

Python 3 data type conversion

Data type conversion refers to the conversion of one data type from the original type to another through some method. For example, we convert the string «123» to the number 123, which is a data type conversion.

Python supports the conversion between various standard data types, but not any data can be converted. All conversions should comply with «common sense» and should be logically valid. For example, you shouldn’t try to convert a complex type to int, because Python doesn’t know how to convert it.

Summary of data type conversion support

Int	Float	Bool	Complex	String	Bytes	List	Tuple	Set	Dict
Int	—	Y	Y	N	Y	Y	N	N	N	N
Float	Y	—	Y	N	Y	Y	N	N	N	N
Bool	Y	Y	—	Y	Y	Y	Y	Y	Y	Y
Complex	Y	Y	Y	—	Y	N	N	N	N	N
String	Y	Y	Y	Y	—	Y	Y	Y	Y	Y
Bytes	Y	N	Y	N	Y	—	Y	Y	Y	N
List	N	N	N	N	Y	Y	—	Y	Y	Y
Tuple	N	N	N	N	Y	Y	Y	—	Y	Y
Set	N	N	N	N	Y	Y	Y	Y	—	Y
Dict	N	N	N	N	Y	N	Y	Y	Y	—

Note: Bytes only considers direct conversion

Conversion instance

Convert to int

print(int(1.2)) # float -> int print(int('123')) # string -> int print(int(b'456')) # bytes -> int print('0x%x' % (int.from_bytes(b'456', byteorder='little', signed=True))) print(int(True)) # bool -> int

Convert to float

print(float('1.2')) # string->float print(float(b'3.4')) # bytes -> float print(float(123)) # int->float print(float(False)) # bool->float

Convert to bool

# All types can be converted to bool print(bool(1)) # int->bool print(bool(0.0)) # float->bool print(bool(0 + 0j)) # complex->bool print(bool('')) # String - > bool, empty string is False, others are True print(bool(b'hello')) # Bytes - > bool, null is False, others are True print(bool.from_bytes(b'\x00', byteorder='little')) # bytes->bool print(bool([])) # List - > bool, null is False, others are True print(bool(())) # Tuple - > bool, null is False, others are True print(bool(<>)) # Dict - > bool, null is False, others are True print(bool(set())) # Set - > bool, null is False, others are True

Convert to complex

print(complex(100)) # int->complex print(complex(1.2)) # float->complex print(complex(True)) # bool->complex print(complex('1.2+2.3j')) # string->complex

Convert to string

# All basic types can be converted to string print(b'hello'.decode('utf-8')) # bytes->string print(str(1)) # int->string print(str(1.2)) # float->string print(str(True)) # bool->string print(str(1.2 + 2.3j)) # Complex - > string all others are True print(str(['hello', 100])) # list->string print(str(('hello', 100))) # tuple->string print(str()) # dict->string print(str()) # set->string

Convert to bytes

# Because all types can be converted to string and string can be converted to bytes, all types can be indirectly converted to bytes. # Next, we will only discuss the type directly converted to bytes print('bytes'.center(30, '*')) print(b'\x64') # int to bytes print(int.to_bytes(100, byteorder='big', signed=True, length=2)) # int to bytes print(bool.to_bytes(True, byteorder='big', signed=True, length=2)) # bool to bytes print('hello'.encode(encoding='utf-8')) # string to bytes print(bytes([1, 200, 80, 50])) # list to bytes print(bytes((1, 200, 80, 50))) # tuple to bytes print(bytes()) # set to bytes

Convert to list

print(list("hello")) # string->list print(list(b'hello')) # bytes->list print(list((100, 200, 300))) # tuple->list print(list()) # set->list print(list()) # Dict - > list, only the key value is taken

Convert to tuple

print(tuple("hello")) # string->tuple print(tuple(b"hello")) # bytes->tuple print(tuple([100, 200, 300])) # list->tuple print(tuple()) # set->tuple print(tuple()) # Dict - > tuple, only the key value is taken

Convert to set

print(set("hello")) # string->set print(set(b"hello")) # bytes->set print(set([100, 200, 300])) # list->set # print(set([100, 200, [300, 400]])) # List - > set, the list contains variable data types, and an exception is reported print(set(('name', 'age'))) # tuple->set # print(set(('name', 'age', []))) # Tuple - > set, including variable data types, and an exception is reported print(set()) # Dict - > set, only the key value is taken

Convert to dict

# Method 1: use json conversion. The string format needs to be strictly in accordance with the json format user_str = '' import json print(json.loads(user_str)) # Mode 2. Use eval function conversion. eval has potential safety hazards and is not recommended print(eval(user_str)) # Method 3: use ast.literal_eval import ast print(ast.literal_eval(user_str))

# Method 1. zip is required user_keys = ['name', 'city', 'age'] user_values = ['xiaowang', 'Chengdu', 28] print(dict(zip(user_keys, user_values))) # Mode 2: 2D list user_info = [ ["name", "xiaowang"], ["city", "Chengdu"], ["age", 28] ] print(dict(user_info))

Set — > dict tuple — > dict is the same as list — > dict

bytearray ⇋ hex

# hex_str-->bytearray byte_array = bytearray.fromhex("050460000008d40462000007670463") print(byte_array) # bytearray-->hex_str hex_str = byte_array.hex() print(hex_str)

# hex_str-->bytearray byte_array = bytearray.fromhex("05 04 60 00 00 08 d4 04 62 00 00 07 67 04 63") print(byte_array) # bytearray-->hex_str hex_str = byte_array.hex() hex_str_space = " ".join([hex_str[i - 1:i + 1] if i % 2 else "" for i in range(len(hex_str))]).strip() print(hex_str_space)

bytearray ⇋ int

import struct # int-->bytearray bytearray_short = struct.pack("int int_short = struct.unpack("
bytearray ⇋ str
# str-->bytearray byte_array = bytearray("liuyang", encoding='utf-8') print(byte_array) # bytearray-->str st_r = byte_array.decode('utf-8') print(st_r)
appendix

'?' The conversion code corresponds to the conversion code defined by C99_ Bool type. If this type is not available, use char to simulate. In standard mode, it is always represented in one byte.
When attempting to package a non integer with any integer conversion code, if the non integer has __index__() Method calls the method before packing and converts the parameter to an integer. Change in version 3.2: added use for non integer __index__() Method.
The 'N' and 'N' conversion codes are only available for native size (select as default or use '@' byte order characters). For standard sizes, you can use any other integer format suitable for your application.
For 'f','d 'and' e 'conversion codes, the packaged representation will use IEEE 754 binary32, binary64 or binary16 format (corresponding to' f ','d' or 'e' respectively), regardless of the floating-point format used by the platform.
'P' format characters are only available for native byte order (select as default or use '@' byte order characters). The byte order character '=' selects to use the small end or large end sorting based on the host system. The struct module will not interpret it as a native sort, so the 'P' format will not be available.
IEEE 754 binary16 "half precision" type is in IEEE 754 standard Introduced in the 2008 revision of. It contains one sign bit, five exponential bits and 11 precision bits (10 bits are explicitly stored), which can completely and accurately represent numbers in the approximate range of 6.1e-05 and 6.5e+04. This type is not widely supported by the C compiler: on a typical machine, unsigned short can be used for storage, but it will not be used for mathematical operations. See Wikipedia page half-precision floating-point format Learn more.

Added by peaforabrain on Wed, 10 Nov 2021 17:15:29 +0200
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Источник
Unsigned integers and Python
The easiest (and portable!) way to get unsigned integers in Python is to import the required types from the ctypes module. However, sometimes you need to convert Pythons ‘normal’ integers to unsigned values. As will be explained, the values are still signed integers (or long), but this has little effect on the application.
If you google python unsigned integer or similar terms, you will find several posts telling you that in order to convert a signed to an unsigned value, it is sufficient to do something similar to:
val & 0xff (val is a 8 bit variable) 
However, few explain why this works. In order to understand why, you first have to know how Python stores a number. Numbers in Python are stored as either signed integers or long, depending on which Python version you use (follow the links here for more information). For example, the following is the case on my machine (which is 64 bit):

>>> val = 9223372036854775807 (maximum value of int 64) >>> type(val) >>> val += 1 >>> type(val)
By increasing the value of val by 1, I exceed the limit of a signed 64 bit integer and the value is converted to a long. If Python had used or converted to an unsigned integer, val would still have been an int. Or, not long.
Signed integers are represented by a bit, usually the most significant bit, being set to 0 for positive numbers or 1 for negative numbers. What val & 0xff does is actually val & 0x000000ff (on a 32 bit machine). In other words, the signed bit is set to 0 and an unsigned value is emulated.
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