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I'm new to LUA but figured out that gsub is a global substitution function and tonumber is a converter function. What I don't understand is how the two functions are used together to produce an encoded string.
I've already tried reading parts of PIL (Programming in Lua) and the reference manual but still, am a bit confused.
local L0_0, L1_1
function L0_0(A0_2)
return (A0_2:gsub("..", function(A0_3)
return string.char((tonumber(A0_3, 16) + 256 - 13 + 255999744) % 256)
end))
end
encodes = L0_0
L0_0 = gg
L0_0 = L0_0.toast
L1_1 = "__loading__\226\128\166"
L0_0(L1_1)
L0_0 = encodes
L1_1 = --"The Encoded String"
L0_0 = L0_0(L1_1)
L1_1 = load
L1_1 = L1_1(L0_0)
pcall(L1_1)
I removed the encoded string where I put the comment because of how long it was. If needed I can upload the encoded string as well.
gsub is being used to get 2 digit sections of A0_2. This means the string A0_3 is a 2 digit hexadecimal number but it is not in a number format so we cannot preform math on the value. A0_3 being a hex number can be inferred based on how tonubmer is used.
tonumber from Lua 5.1 Reference Manual:
Tries to convert its argument to a number. If the argument is already a number or a string convertible to a number, then tonumber returns this number; otherwise, it returns nil.
An optional argument specifies the base to interpret the numeral. The base may be any integer between 2 and 36, inclusive. In bases above 10, the letter 'A' (in either upper or lower case) represents 10, 'B' represents 11, and so forth, with 'Z' representing 35. In base 10 (the default), the number can have a decimal part, as well as an optional exponent part (see §2.1). In other bases, only unsigned integers are accepted.
So tonumber(A0_3, 16) means we are expecting for A0_3 to be a base 16 number (hexadecimal).
Once we have the number value of A0_3 we do some math and finally convert it to a character.
function L0_0(A0_2)
return (A0_2:gsub("..", function(A0_3)
return string.char((tonumber(A0_3, 16) + 256 - 13 + 255999744) % 256)
end))
end
This block of code takes a string of hex digits and converts them into chars. tonumber is being used to allow for the manipulation of the values.
Here is an example of how this works with Hello World:
local str = "Hello World"
local hex_str = ''
for i = 1, #str do
hex_string = hex_string .. string.format("%x", str:byte(i,i))
end
function L0_0(A0_2)
return (A0_2:gsub("..", function(A0_3)
return string.char((tonumber(A0_3, 16) + 256 - 13 + 255999744) % 256)
end))
end
local encoded = L0_0(hex_str)
print(encoded)
Output
;X__bJbe_W
And taking it back to the orginal string:
function decode(A0_2)
return (A0_2:gsub("..", function(A0_3)
return string.char((tonumber(A0_3, 16) + 13) % 256)
end))
end
hex_string = ''
for i = 1, #encoded do
hex_string = hex_string .. string.format("%x", encoded:byte(i,i))
end
print(decode(hex_string))
I look some solution in this site but those not works in python 3.7.
So, I asked a new question.
Hex string of "the" is "746865"
I want to a solution to convert "the" to "746865" and "746865" to "the"
Given that your string contains ascii only (each char is in range 0-0xff), you can use the following snippet:
In [28]: s = '746865'
In [29]: import math
In [30]: int(s, base=16).to_bytes(math.ceil(len(s) / 2), byteorder='big').decode('ascii')
Out[30]: 'the'
Firstly you need to convert a string into integer with base of 16, then convert it to bytes (assuming 2 chars per byte) and then convert bytes back to string using decode
#!/usr/bin/python3
"""
Program name: txt_to_ASC.py
The program transfers
a string of letters -> the corresponding
string of hexadecimal ASCII-codes,
eg. the -> 746865
Only letters in [abc...xyzABC...XYZ] should be input.
"""
print("Transfer letters to hex ASCII-codes")
print("Input range is [abc...xyzABC...XYZ].")
print()
string = input("Input set of letters, eg. the: ")
print("hex ASCII-code: " + " "*15, end = "")
def str_to_hasc(x):
global glo
byt = bytes(x, 'utf-8')
bythex = byt.hex()
for b1 in bythex:
y = print(b1, end = "")
glo = str(y)
return glo
str_to_hasc(string)
If you have a byte string, then:
>>> import binascii
>>> binascii.hexlify(b'the')
b'746865'
If you have a Unicode string, you can encode it:
>>> s = 'the'
>>> binascii.hexlify(s)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: a bytes-like object is required, not 'str'
>>> binascii.hexlify(s.encode())
b'746865'
The result is a byte string, you can decode it to get a Unicode string:
>>> binascii.hexlify(s.encode()).decode()
'746865'
The reverse, of course, is:
>>> binascii.unhexlify(b'746865')
b'the'
#!/usr/bin/python3
"""
Program name: ASC_to_txt.py
The program's input is a string of hexadecimal digits.
The string is a bytes object, and each byte is supposed to be
the hex ASCII-code of a (capital or small) letter.
The program's output is the string of the corresponding letters.
Example
Input: 746865
First subresult: ['7','4','6','8','6','5']
Second subresult: ['0x74', '0x68', '0x65']
Third subresult: [116, 104, 101]
Final result: the
References
Contribution by alhelal to stackoverflow.com (20180901)
Contribution by QintenG to stackoverflow.com (20170104)
Mark Pilgrim, Dive into Python 3, section 4.6
"""
import string
print("The program converts a string of hex ASCII-codes")
print("into the corresponding string of letters.")
print("Input range is [41, 42, ..., 5a] U [61, 62, ..., 7a]. \n")
x = input("Input the hex ASCII-codes, eg. 746865: ")
result_1 = []
for i in range(0,len(x)//2):
for j in range(0,2):
result_1.extend(x[2*i+j])
# First subresult
lenres_1 = len(result_1)
result_2 = []
for i in range(0,len(result_1) - 1,2):
temp = ""
temp = temp + "0x" + result_1[i] #0, 2, 4
temp = temp + result_1[i + 1] #1, 3, 5
result_2.append(temp)
# Second subresult
result_3 = []
for i in range(0,len(result_2)):
result_3.append(int(result_2[i],16))
# Third subresult
by = bytes(result_3)
result_4 = by.decode('utf-8')
# Final result
print("Corresponding string of letters:" + " "*6, result_4, end = "\n")
I am trying to compare the input string with the strings present in the doc. I am using strcmp for the purpose. These are non-English strings. When the input string is English language, the output is correct. But for any Kannada (non-English language) word the output is the same. I am trying to write a program to check if the word is present in the database. Please guide me in what could be the problem.
The calling function is as below:
str_kan = handles.InputBox.String;
res = strcmp('str_kan','s1.text')
if res == 1 then handles.InputBox.String = string( ' present')
abort
else
handles.InputBox.String = string( 'not present')
abort
end
The whole program is as below:
global s1
f=figure('figure_position',[400,50],'figure_size',[640,480],'auto_resize','on','background',[33],'figure_name','Graphic window number %d','dockable','off','infobar_visible','off','toolbar_visible','off','menubar_visible','off','default_axes','on','visible','off');
handles.dummy = 0;
handles.InputBox=uicontrol(f,'unit','normalized','BackgroundColor',[-1,-1,-1],'Enable','on','FontAngle','normal','FontName','Tunga','FontSize',[12],'FontUnits','points','FontWeight','normal','ForegroundColor',[-1,-1,-1],'HorizontalAlignment','left','ListboxTop',[],'Max',[1],'Min',[0],'Position',[0.0929487,0.6568182,0.4647436,0.1795455],'Relief','default','SliderStep',[0.01,0.1],'String','Enter a Kannada Word','Style','edit','Value',[0],'VerticalAlignment','middle','Visible','on','Tag','InputBox','Callback','')
handles.CheckDB=uicontrol(f,'unit','normalized','BackgroundColor',[-1,-1,-1],'Enable','on','FontAngle','normal','FontName','Tahoma','FontSize',[12],'FontUnits','points','FontWeight','normal','ForegroundColor',[-1,-1,-1],'HorizontalAlignment','center','ListboxTop',[],'Max',[1],'Min',[0],'Position',[0.1025641,0.4636364,0.4567308,0.1204545],'Relief','default','SliderStep',[0.01,0.1],'String','Check','Style','pushbutton','Value',[0],'VerticalAlignment','middle','Visible','on','Tag','CheckDB','Callback','CheckDB_callback(handles)')
f.visible = "on";
function CheckDB_callback(handles)
str_kan = handles.InputBox.String;
res = strcmp('str_kan','s1.text')
if res == 1 then handles.InputBox.String = string( ' present')
abort
else
handles.InputBox.String = string( 'not present')
abort
end
endfunction
Here is an example showing that, in Scilab, strcmp() does support UTF-8 extended characters:
--> strcmp(["aα" "aα" "aβ"], ["aα" "aβ" "aα"])
ans =
0. -1. 1.
The problem in the original posted code is the confusion between literal values as "Hello" and variables names as Hello="my text", as already noted by PTRK.
This question already has answers here:
What is the difference between __str__ and __repr__?
(28 answers)
Closed 2 years ago.
I really don't understand where are __str__ and __repr__ used in Python. I mean, I get that __str__ returns the string representation of an object. But why would I need that? In what use case scenario? Also, I read about the usage of __repr__
But what I don't understand is, where would I use them?
__repr__
Called by the repr() built-in function and by string conversions (reverse quotes) to compute the "official" string representation of an object. If at all possible, this should look like a valid Python expression that could be used to recreate an object with the same value (given an appropriate environment).
__str__
Called by the str() built-in function and by the print statement to compute the "informal" string representation of an object.
Use __str__ if you have a class, and you'll want an informative/informal output, whenever you use this object as part of string. E.g. you can define __str__ methods for Django models, which then gets rendered in the Django administration interface. Instead of something like <Model object> you'll get like first and last name of a person, the name and date of an event, etc.
__repr__ and __str__ are similar, in fact sometimes equal (Example from BaseSet class in sets.py from the standard library):
def __repr__(self):
"""Return string representation of a set.
This looks like 'Set([<list of elements>])'.
"""
return self._repr()
# __str__ is the same as __repr__
__str__ = __repr__
The one place where you use them both a lot is in an interactive session. If you print an object then its __str__ method will get called, whereas if you just use an object by itself then its __repr__ is shown:
>>> from decimal import Decimal
>>> a = Decimal(1.25)
>>> print(a)
1.25 <---- this is from __str__
>>> a
Decimal('1.25') <---- this is from __repr__
The __str__ is intended to be as human-readable as possible, whereas the __repr__ should aim to be something that could be used to recreate the object, although it often won't be exactly how it was created, as in this case.
It's also not unusual for both __str__ and __repr__ to return the same value (certainly for built-in types).
Building up and on the previous answers and showing some more examples. If used properly, the difference between str and repr is clear. In short repr should return a string that can be copy-pasted to rebuilt the exact state of the object, whereas str is useful for logging and observing debugging results. Here are some examples to see the different outputs for some known libraries.
Datetime
print repr(datetime.now()) #datetime.datetime(2017, 12, 12, 18, 49, 27, 134411)
print str(datetime.now()) #2017-12-12 18:49:27.134452
The str is good to print into a log file, where as repr can be re-purposed if you want to run it directly or dump it as commands into a file.
x = datetime.datetime(2017, 12, 12, 18, 49, 27, 134411)
Numpy
print repr(np.array([1,2,3,4,5])) #array([1, 2, 3, 4, 5])
print str(np.array([1,2,3,4,5])) #[1 2 3 4 5]
in Numpy the repr is again directly consumable.
Custom Vector3 example
class Vector3(object):
def __init__(self, args):
self.x = args[0]
self.y = args[1]
self.z = args[2]
def __str__(self):
return "x: {0}, y: {1}, z: {2}".format(self.x, self.y, self.z)
def __repr__(self):
return "Vector3([{0},{1},{2}])".format(self.x, self.y, self.z)
In this example, repr returns again a string that can be directly consumed/executed, whereas str is more useful as a debug output.
v = Vector3([1,2,3])
print str(v) #x: 1, y: 2, z: 3
print repr(v) #Vector3([1,2,3])
One thing to keep in mind, if str isn't defined but repr, str will automatically call repr. So, it's always good to at least define repr
Grasshopper, when in doubt go to the mountain and read the Ancient Texts. In them you will find that __repr__() should:
If at all possible, this should look like a valid Python expression that could be used to recreate an object with the same value.
Lets have a class without __str__ function.
class Employee:
def __init__(self, first, last, pay):
self.first = first
self.last = last
self.pay = pay
emp1 = Employee('Ivan', 'Smith', 90000)
print(emp1)
When we print this instance of the class, emp1, this is what we get:
<__main__.Employee object at 0x7ff6fc0a0e48>
This is not very helpful, and certainly this is not what we want printed if we are using it to display (like in html)
So now, the same class, but with __str__ function:
class Employee:
def __init__(self, first, last, pay):
self.first = first
self.last = last
self.pay = pay
def __str__(self):
return(f"The employee {self.first} {self.last} earns {self.pay}.")
# you can edit this and use any attributes of the class
emp2 = Employee('John', 'Williams', 90000)
print(emp2)
Now instead of printing that there is an object, we get what we specified with return of __str__ function:
The employee John Williams earns 90000
str will be informal and readable format whereas repr will give official object representation.
class Complex:
# Constructor
def __init__(self, real, imag):
self.real = real
self.imag = imag
# "official" string representation of an object
def __repr__(self):
return 'Rational(%s, %s)' % (self.real, self.imag)
# "informal" string representation of an object (readable)
def __str__(self):
return '%s + i%s' % (self.real, self.imag)
t = Complex(10, 20)
print (t) # this is usual way we print the object
print (str(t)) # this is str representation of object
print (repr(t)) # this is repr representation of object
Answers :
Rational(10, 20) # usual representation
10 + i20 # str representation
Rational(10, 20) # repr representation
str and repr are both ways to represent. You can use them when you are writing a class.
class Fraction:
def __init__(self, n, d):
self.n = n
self.d = d
def __repr__(self):
return "{}/{}".format(self.n, self.d)
for example when I print a instance of it, it returns things.
print(Fraction(1, 2))
results in
1/2
while
class Fraction:
def __init__(self, n, d):
self.n = n
self.d = d
def __str__(self):
return "{}/{}".format(self.n, self.d)
print(Fraction(1, 2))
also results in
1/2
But what if you write both of them, which one does python use?
class Fraction:
def __init__(self, n, d):
self.n = n
self.d = d
def __str__(self):
return "str"
def __repr__(self):
return "repr"
print(Fraction(None, None))
This results in
str
So python actually uses the str method not the repr method when both are written.
Suppose you have a class and wish to inspect an instance, you see the print doesn't give much useful information
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
p1 = Person("John", 36)
print(p1) # <__main__.Animal object at 0x7f9060250410>
Now see a class with a str, it shows the instance information and with repr you even don't need the print. Nice no?
class Animal:
def __init__(self, color, age, breed):
self.color = color
self.age = age
self.breed = breed
def __str__(self):
return f"{self.color} {self.breed} of age {self.age}"
def __repr__(self):
return f"repr : {self.color} {self.breed} of age {self.age}"
a1 = Animal("Red", 36, "Dog")
a1 # repr : Red Dog of age 36
print(a1) # Red Dog of age 36
Code:
SHA1 sha = new SHA1CryptoServiceProvider();
string hashedValue = string.Empty;
//hash the data
byte[] hashedData = sha.ComputeHash(Encoding.Unicode.GetBytes(str));
//loop through each byte in the byte array
foreach (byte b in hashedData)
{
//convert each byte and append
hashedValue += String.Format("{0,2:X2}", b);
}
I searched for arguments passed to String.Format() but didnt able to understand it exactly.
Thanks in advance!
Formatting the string in hexadecimal format...
X = Hexadecimal format
2 = 2 characters
It's basically just formatting the string in uppercase hexadecimal format - see the docs.
The hexadecimal ("X") format specifier converts a number to a string of hexadecimal digits. The case of the format specifier indicates whether to use uppercase or lowercase characters for hexadecimal digits that are greater than 9.
This particular format is known as Composite Formatting, so to break it down:
{0 = parameterIndex, 2 = alignment :X2 = formatString}