Im trying to incorporate my encryption program into a chat program. But i cant pass a MutableString with Socket. So how would I properly covert my MutableString into a proper string?
import sys
from UserString import MutableString
def GetMode():
while True:
print '\n(E)ncrypt Or (D)ecrypt?'
Mode = raw_input().lower()
if Mode in 'e d encrypt decrypt'.split():
return Mode
else:
print '\nEnter Proper Choice!'
def GetInput():
while True:
print '\n(T)ype Message Or (L)oad File?'
Input = raw_input().lower()
if Input in 't type'.split():
Input = raw_input('>')
return Input
elif Input in 'l load'.split():
MsgLoc = raw_input()
MsgLoc = open(MsgLoc, 'r')
try:
Input = MsgLoc.read()
MsgLoc.close()
return Input
except:
print '\nCould Not Open' , MsgLoc
else:
print '\nEnter Proper Choice!'
def GetKey():
while True:
Key = 0
print '\nPlease Enter A 20 Digit Number...\n** Do NOT use zeros!!!! EX-NAY ERO-ZAY! **'
try:
Key = int(input())
Key = str(Key)
if (len(Key) == 20):
return Key
else:
print('\nPlease Enter A Valid Number!')
except:
print('\nPlease Enter A Valid Number!')
def Translate(Mode, Input, Key):
if Mode[0] == 'e':
print('\nEncrypting....')
Encrypt(Input, Key)
else:
print('\nDecrypting....')
Decrypt(Input, Key)
def Encrypt(Input, Key):
Msg = MutableString()
NonMutMsg = Input
Msg += NonMutMsg
MsgLen = len(Msg)
CypherKey = Key
a = 0
b = 19
#Loop For Proccessing Key
for z in range(10):
KeySkip = int(CypherKey[a])
KeyIncrement = int(CypherKey[b])
c = MsgLen/KeySkip
d = -1
#Loop To Skip Then Increment
for y in range(c):
d = d+KeySkip
LtrNum = ord(NonMutMsg[d])
LtrNum = LtrNum + KeyIncrement
Msg[d] = chr(LtrNum)
First of all, as the MutableString documentation states:
It should be noted that these classes are highly inefficient compared to real string or Unicode objects; this is especially the case for MutableString.
and most importantly:
The main intention of this class is to serve as an educational example for inheritance
In other words, don't use this class in real world code.
To get the data out, use the data parameter:
pythonstring = mutablestring.data
Related
I am writing a program to encrypt / decrypt an inputted message using a key generated from a pool
The pool is created by appending unicode characters to an array
When selecting option 2 (encrypt) and reading the genkey.txt file (after generating the key with option 1), the program shows an index error as shown:
Exception has occurred: IndexError
list index out of range, line 58, in b = keyarray[a]
However, when removing the unicode script and replacing the pool with plain text (e.g [a, b, c...]) the message is encrypted without any issue.
Any way to fix this?
Code:
import random
programrun = 0
encryptedarray = []
decryptedarray = []
keyarray = []
while programrun < 1:
pool = []
for i in range(32,123): #Unicode characters
pool.append(chr(i))
print("Encryption / Decryption")
print("")
print("1. Generate Key")
print("2. Encrypt")
print("3. Decrypt")
print("4. Quit")
print("NOTE: Key must be generated before selecting Encryption / Decryption")
print("")
option = int(input("Enter the number corresponding to the option: "))
if option == 1:
a = 20
while a > 0:
b = random.randint(0,57)
c = pool[b]
keyarray.append(c)
a = a - 1
keygen = ("".join(keyarray))
print("Your generated key is:", keygen)
print("")
print("(Make sure you have generated a key before typing 'yes')")
writebool = input("Do you want to save the file to your computer? ")
if writebool == "yes":
keyfile = open("genkey.txt", "x")
keyfile.write(keygen)
keyfile.close()
wbval = 1
print("File saved to genkey.txt successfully")
print("")
quitval = 1
elif writebool == "no":
print("ok")
else:
print("Type yes or no")
elif option == 2:
encryptvalid = 0
while encryptvalid < 1:
msg = str(input("Enter the message to be encrypted: "))
genkeyf = open("genkey.txt", "r")
genkeydata = genkeyf.read()
if genkeydata == keygen:
print("File VALID")
encryptvalid = 1
for i in msg:
a = pool.index(i)
b = keyarray[a]
encryptedarray.append(b)
p = ("".join(encryptedarray))
print("")
print("Your encrypted string is: ")
print("".join(encryptedarray))
else:
print("File INVALID")
print("Please check if the genkey.txt file matches the current generated key.")
a = pool.index(i) looks up the index of a character of the message in the pool, then that index is used to lookup a value in the keyarray with b = keyarray[a].
pool is 91 bytes long, but keyarray is 20 bytes long, so many of the indexes are too high. You probably want b = keyarray[a % len(keyarray)]. This uses the modulus operator to constrain the lookup from 0-19.
This program essentially encodes and decodes a message and code respectively. I only did the decoding part so far. However I keep getting an EOF error even though I made sure to end parentheses, checked my syntax and kept tampering with it. Unfortunately no luck. Anyone know why this error keeps popping up? I would greatly appreciate it. Also I copied both files that i'm using.
from LetterCodeLogic import LCL
def main():
print("Welcome to the LetterCode program")
choice = getChoice()
while choice !=0:
if choice == 1:
#Encode logic...
print()
elif choice == 2:
#Decode logic...
msg = input("Enter your numbers to decode (separate with commas): ")
#send msg to Decode function in LCL class (LetterCodeLogic.py file)
result = LCL.Decode(msg)
print("Your decoded message is: \n" + result)
else:
print("Unknown process...")
print()
choice = getChoice()
print("Thanks for using the Letter Code program")
def getChoice():
c = int(input("Choice? (1=Encode, 2=Decode, 0=Quit): "))
return c
if __name__ == "__main__":
main()
class LCL:
"""Encode/Decode Functions"""
#staticmethod
def Decode(msg):
#separate numbers from msg string (e.g., "1,2,3")
nums = msg.split(",") #produces list of separate items
result = ""
for x in nums:
try:
n = int(x.strip()) #remove leading/trailing spaces...
if n == 0:
c = " "
elif n < 0 or n > 26:
c = "?"
else:
#ASCII scheme has A=65, B=66, etc.
c = chr(n+64)
except ValueError:
c = "?"
result += c #same as: result = result + c
return result
#staticmethod
def Encode(msg):
the "#staticmethod" and "def Encode()" function was empty and that was the end of line parsing error. When I was coding this and ran it, it ran with no problems. So I removed it for the time being.
I am needing a bit of help on my encryption program. Instead of having the program just move the letters by two (c would become a or r would become p) I'd like to be able to have it reference 2 lists, the first one going from a-z normally and the other with letters in different order to act as the encrypt/decrypt side. Hopefully that makes sense. Here's what i have so far.
result = ''
choice = ''
message = ''
while choice != 0:
choice = input("\n Do you want to encrypt or decrypt the message?\n 1 to encrypt, 2 to decrypt or 0 to exit program. ")
if choice == '1':
message = input('\nEnter message for encryption: ')
for i in range(0, len(message)):
result = result + chr(ord(message[i]) - 2)
print(result + '\n\n')
result = ''
if choice == '2':
message = input('\nEnter message to decrypt: ')
for i in range(0, len(message)):
result = result + chr(ord(message[i]) + 2)
print(result + '\n\n')
result = ''
elif choice != '0':
print('You have entered an invalid input, please try again. \n\n')
This works fine and dandy but i'd like to have the lists. Lets say list 1 is A,B,C,D,E and list 2 would be W,N,U,D,P. just for ease of use purposes.
Here is a solution, for small letters only. It can easily be modified to handle also capital letters, by adding them to the text strings.
As can be seen, the space character is at the same position in both lists. This is not necessary, as any character can be translated to any other. However if the decrypted or encrypted is not containing unique characters only, the program will break down.
decrypted = b"abcdefghijklmnopqrstuvwxyz "
encrypted = b"qwertyuiopasdfghjklzxcvbnm "
encrypt_table = bytes.maketrans(decrypted, encrypted)
decrypt_table = bytes.maketrans(encrypted, decrypted)
result = ''
choice = ''
message = ''
while choice != '0':
choice = input("\n Do you want to encrypt or decrypt the message?\n 1 to encrypt, 2 to decrypt or 0 to exit program. ")
if choice == '1':
message = input('\nEnter message for encryption: ')
result = message.translate(encrypt_table)
print(result + '\n\n')
elif choice == '2':
message = input('\nEnter message to decrypt: ')
result = message.translate(decrypt_table)
print(result + '\n\n')
elif choice != '0':
print('You have entered an invalid input, please try again. \n\n')
Ok, so a few things here...
First I'll give you exactly what you were looking for and explain what I used and some of the changes that needed to be made to your original code. Then I'll explain some inherent issues what what you're trying to do and suggest some areas to read up on/some ways you might want to improve what you've got.
Here's the code you're looking for (while retaining the same flow as what you submitted put above):
import random
result = ''
choice = ''
message = ''
characters_in_order = [chr(x) for x in range(32,127)]
while choice != 0:
choice = input("\n Do you want to encrypt or decrypt the message?\n 1 to encrypt, 2 to decrypt or 0 to exit program. ")
if str(choice) == '1':
message = input('\nEnter message for encryption: ')
r_seed = input('Enter an integer to use as a seed: ')
random.seed(r_seed)
shuffled_list = [chr(x) for x in range(32,127)]
random.shuffle(shuffled_list)
for i in range(0, len(message)):
result += shuffled_list[characters_in_order.index(message[i])]
print(result + '\n\n')
result = ''
elif str(choice) == '2':
message = input('\nEnter message to decrypt: ')
r_seed = input('Enter an integer to use as a seed (should be the same one used to encrypt): ')
random.seed(r_seed)
shuffled_list = [chr(x) for x in range(32,127)]
random.shuffle(shuffled_list)
for i in range(0, len(message)):
result += characters_in_order[shuffled_list.index(message[i])]
print(result + '\n\n')
result = ''
elif str(choice) != '0':
print('You have entered an invalid input, please try again. \n\n')
You'll notice that I set a global 'characters in order' list, which is just every ASCII character (32-126) in order. I also imported the 'random' module and used this to shuffle the characters in order according to a seed that the user inputs. As long as this seed is the same on the encryption and decryption end, it will produce the same shuffled list and it should work to encrypt or decipher the same string. Also notice the str() around your input choices. Without that, the user had to input '1', rather than 1 to submit a choice without an error.
All of that said...
Notice that the way the new function works is by looking at a character's index in one list and pulling out the character at that index in another. The method you were using, of incrementing or decrementing a character's ASCII code is basic (though not much more basic than this), but it also has a pretty critical flaw, which is that characters on one end or another of the ASCII set wouldn't return ASCII characters. If you were encrypting it at a bit-level, which would be preferred, this wouldn't matter/would be irrelevant, but here you're not going to get the kind of string back that you want if you were to, for example, enter a [space] (ASCII 32) into your plaintext to be encrypted.
If you're interested, you might want to read up on symmetric key encryption/DES for some ideas on how encryption is really done, though props on the start/interest and this can certainly be a fun way to create some sort of cryptogram puzzle or something along those lines. I won't pretend to be any kind of expert, but I can at least point you in the write direction. (https://en.wikipedia.org/wiki/Data_Encryption_Standard https://en.wikipedia.org/wiki/Symmetric-key_algorithm)
Consider having your code read in a .txt file and print out to a .txt file, rather than using user input for the message.
Again, I'm not an expert by any means and there are definitely some fun uses of the kind of program you're aiming for, just trying to point you in the right direction if this is something that you're interested in. Hope all of that is helpful!
Here is my solution. It uses a randomizer to encrypt the file by assigning a ASCII value to the plain text and randomly shifts it around.
from random import randint
import sys
def menu():
input1=int(input(""" please select what you want to do:
1.Encrypt
2.Decrypt
3.Extended Encryption
4.exit
"""))#menu to choose what you want to do
if input1==1:
encrypt() #takes you to the encrypt function
elif input1==2:
decrypt()#takes you to the decrypt function
elif input1==3:
enxtended()#takes you to the extended encryption function
elif input1==4:
sys.exit #exits the program
else:
print("invalid entry try again")
menu()
def encrypt():
file_name=str(input("please enter the name of the file that you want to open\n"))
try:
text_file=open(file_name + ".txt","r")#puts the text file into read
text_file=text_file.read()#reads the text file
print(text_file)#prints the strings in the document
except:
print("error try again")
encrypt()
random(text_file)
def random(text_file):
list1=("")#creates blank string
for x in range (0,8):
num=(randint(33,126))#generates a random number between33 and 126
ascii1=chr(num) #converts it into an ascii character
list1=list1+ascii1#adds the ascii character to the blank string list1
print (f"your 8 key code is {list1}") #prints 8 character code
offset(list1,text_file)
def offset(list1,text_file):
total=0
for x in range (8,):
total=total+ord(list1[x]) #turns each character into an ascii value
total=total/8 #divides it by
total=round(total,0)#rounds it to 0 decimel places
print(total)
total=total-32#minuses 32 from total
print(f"your offset factor is {total}")
encrypting(total,text_file)
def encrypting(total,text_file):
length=len(text_file)
string1=("")
for x in range (length,):
numascii=ord(text_file[x])#turns the characters into its ascii value
numascii=int(numascii)#makes sure they are integers
if numascii==32:
letter=chr(32)#converts spaces back into spaces
string1=string1+letter#adds space to thestring
else:
numascii1=numascii+total#adds the character value to the offset factor
numascii1=int(numascii1)#makes sure it is an integer
if numascii1>126:# if the ascii value is great then 126
numascii1=numascii1-94#minus 94 from it
letter=chr(numascii1)#turn it into a character
string1=string1+letter#add it to the string
else:
letter=chr(numascii1)#turn the ascii value into a character
string1=string1+letter#add it to the string
print(f"your encrypted file is {string1}")
savefile(string1)
menu()
I have written separate programs for encryption and decryption. Both of these use file manipulation techniques. Use the username 'eggs' and password 'chicks' so that not anyone can see my secret code. I have used hashlib for more security. Just change the User 'Soumajit' to your respective Username to make it work. The first one is encryption and the next one is for decryption.
#ENCRYPTION
from time import sleep
import subprocess
import hashlib
def copy2clip(txt):
cmd='echo '+txt.strip()+'|clip'
return subprocess.check_call(cmd, shell=True)
def en():
alphabet = "abcdefghijklmnopqsrtuwvxyzABCDEFGHIJKLMNOPQSRTUVWXYZ,./?:;!##$%_&* ()`-+=1234567890"
encrypt = ""
decrypt = ""
print
print "Type y for yes and anything else for no"
start = raw_input("Do you want to import file from desktop? ")
if start == "y":
Open = raw_input("Enter the .txt file you want to open in desktop: ")
a = open("C://Users//Soumajit//Desktop//" + Open + ".txt", "r")
print
x = (a.read())
copy2clip(x)
a.close()
print "Right click and select paste below to encrypt"
print
message = raw_input()
for i in message:
x = alphabet.find(i)
new = (x - 5) % 74
encrypt += alphabet[new]
e2 = encrypt[::-1]
else:
print "Type your message below"
message = raw_input("")
for i in message:
x = alphabet.find(i)
new = (x - 5) % 74
encrypt += alphabet[new]
e2 = encrypt[::-1]
print
a = raw_input("By what name do you want to save it?: ")
file = open(a + ".txt", 'wb')
file.write(e2)
file.close()
copy = raw_input("Do you want to copy your file? ")
if copy == 'y':
copy2clip(e2)
print 'Your encrypted file has been copied to the clipboard'
else:
print "Your encrypted file has been saved with the name " + str(a) + " in desktop"
print "To decrypt it, use my other program"
sleep(3)
u = 'e415bf03b4d860dccba57cea46371f831d772ba1deca47f28fa7d1f7'
p = 'c35f7f79dc34a678beb2b4106c84c9963561e7c64bc170e50c429b9a'
ur = raw_input('Enter your username: ')
ur1 = hashlib.sha224(ur).hexdigest()
pr = raw_input('Enter your password: ')
pr1 = hashlib.sha224(pr).hexdigest()
if ur1 == u and pr1 == p:
print 'Access granted'
sleep(1)
en()
else:
print "Incorrect username or password"
sleep(1)
#DECRYPTION
from time import sleep
import subprocess
import hashlib
def copy2clip(txt):
cmd='echo '+txt.strip()+'|clip'
return subprocess.check_call(cmd, shell=True)
def de():
print "Type y for yes and anything else for no"
start = raw_input("Do you want to import file from desktop? ")
if start == "y":
Open = raw_input("Enter the .txt file you want to open from folder: ")
a = open("C://Users//Soumajit//Desktop//" + Open + ".txt", "r")
x = (a.read())
#print x
copy2clip(x)
print "Right click and select paste below to decrypt"
print
message = raw_input()
a.close()
alphabet = "abcdefghijklmnopqsrtuwvxyzABCDEFGHIJKLMNOPQSRTUVWXYZ,./?:;!##$%_&*()`-+=1234567890"
decrypt = ''
for i in message:
x = alphabet.find(i)
new = (x + 5) % 74
decrypt += alphabet[new]
d2 = decrypt[::-1]
d3 = d2.replace("`", " ")
final = d3.replace("2", " ")
print
print final
else:
print "Type or paste your encrypted text below"
print
message = raw_input()
alphabet = "abcdefghijklmnopqsrtuwvxyzABCDEFGHIJKLMNOPQSRTUVWXYZ,./?:;!##$%_&*()`-+=1234567890"
decrypt = ''
for i in message:
x = alphabet.find(i)
new = (x + 5) % 74
decrypt += alphabet[new]
d2 = decrypt[::-1]
d3 = d2.replace("`", " ")
final = d3.replace("2", " ")
print
print final
u = 'e415bf03b4d860dccba57cea46371f831d772ba1deca47f28fa7d1f7'
p = 'c35f7f79dc34a678beb2b4106c84c9963561e7c64bc170e50c429b9a'
ur = raw_input('Enter your username: ')
ur1 = hashlib.sha224(ur).hexdigest()
pr = raw_input('Enter your password: ')
pr1 = hashlib.sha224(pr).hexdigest()
if ur1 == u and pr1 == p:
print 'Access granted'
sleep(1)
de()
print
end = raw_input('press q to quit: ')
while end != 'q':
print 'You did not type q'
end = raw_input('press q to quit: ')
if end == 'q':
quit()
else:
print 'Incorrect username or password'
sleep(1)
quit()
Hello guys I am a beginner at python and was trying to make an Encryption code which uses an encryption key defined by me for example I made this code but it isn't working:
def encrypt():
A = "f"
B = "d"
C = "z"
T = "x"
first = input()
print(first)
I want the program to function like when a user enters CAT in the input the output should be zax but when I input even A in my current program it prints
A as it is.
Any help would be appreciated!
You can just use string.translate method. A sample code would be:
def encrypt():
encryption_table = {
ord('A'):ord('f'),
ord('B'):ord('d'),
ord('C'):ord('z'),
ord('T'):ord('x'),
}
first = input()
print(first.translate(encryption_table))
For this code an input CAT will return zfx.
First you should make a dictionary to map your letter substitution , eg :
my_dict = { 'A':'f', 'B':'d', 'C':'z', 'T':'x', ... }
Then you need an encrypt function to return the values of this dictionary :
def encrypt(data):
return ''.join( my_dict[d] if d in my_dict else d for d in data )
And a decrypt function that does the opposite :
def decrypt(data):
my_dict_rev = dict((v,k) for k,v in my_dict.items())
return ''.join( my_dict_rev[d] if d in my_dict_rev else d for d in data )
Now lets test it :
my_data = 'TEST DATA'
enc_data = encrypt(my_data)
dec_data = decrypt(enc_data)
Output :
print(my_data)
print(enc_data)
print(dec_data)
TEST DATA
xESx Dfxf
TEST DATA
Here is a simple encryption and decryption script if you want to use it. The password part can be left out or you can leave it in. The same goes with the loading bar. the loading bar is on lines 1-4 and the password is on the last 9 lines. If you do take out the password make sure to call start. you will also need to install tqdm through pip.
import time
from tqdm import *
for i in tqdm(range(1000)):
time.sleep(0.001)
def encrypt(some_string):
alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
cipher = 'bcdefghijklmnopqrstuvwxyzaBCDEFGHIJKLMNOPQRSTUVWXYZA'
encryption = ''
for char in some_string:
if(alphabet.find(char) == -1):
encryption = encryption + char
else:
position = alphabet.index(char)
encryption = encryption + cipher[position]
return encryption
def decrypt(some_string):
cipher = 'bcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZa'
alphabet = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
decryption = ''
for char in some_string:
if(cipher.find(char) == -1):
decryption = decryption + char
else:
position = cipher.index(char)
decryption = decryption + alphabet[position]
return decryption
def restart():
print('Would you like to restart.')
print('1: Yes.')
print('2: No.')
c = float(input('Type a 1 or a 2: '))
if c == 1:
print('Ok you can restart.')
start()
if c == 2:
print('Sorry to see you leave.')
quit()
else:
print('Invalid response.')
restart()
def start():
print('1: Encryption')
print('2: Decryption')
e = float(input('Type a 1 or a 2: '))
if e == 1:
print('Type your message here.')
e = str(input('Enter message to encrypt: '))
print(encrypt(e))
restart()
if e == 2:
print('Type your messed up message here.')
e = str(input('Enter your messed up message: '))
print(decrypt(e))
restart()
else:
print('Please type a 1 or a 2.')
start()
def password():
a = float(input('Enter the correct password please: '))
if a == 5194703:
print('Correct!')
start()
else:
print('Invalid Password, try again!')
password()
password()
I want to be able to have a program whereby the user can input a paragraph/sentence/word/character whatever and have that stored in a list e.g. in list[0]. Then I want them to be able to write another bit of text and have that stored in e.g. list[1]. Then at any time I want the user to be able to read that from the list by choosing which segment they want to read from e.g. reading "hello" from list[0] whilst in list[1] "hi" is stored. Then when the user exits the program I want the list to be written to an external file. Then, at next start up, the program should read the file contents and store it again in the list so that the user can add more bits of text or read the current bits. When the list is saved to a file it should append new or changed parts but overwrite parts that are the same so as not to have duplicates. I have attempted this without much success. I am to be honest not sure if it is possible. I have browsed similar forums and have found that hasn't helped much so here it is.
My code so far:
import os
import time
import csv
global write_list
global f1_contents
write_list = []
def write():
os.system("cls")
user_story = input("Enter your text: \n")
write_list.append(user_story)
def read():
os.system("cls")
user_select_needs = True
while user_select_needs == True:
user_select = input("Enter the list section to read from or type exit: \n")
if user_select == "exit":
user_select_needs = False
try:
int(user_select)
select = user_select
select = int(select)
try:
print(write_list[select])
user_select_needs = False
enter = input("Press enter:")
except:
print("There is not stored data on that section!")
except ValueError:
print("That is not a valid section!")
def exit():
os.system("cls")
max_num_needs = True
while max_num_needs == True:
set_max_num = input("Set the storage: \n")
try:
int(set_max_num)
max_num = set_max_num
max_num = int(max_num)
max_num_needs = False
except:
print("It must be an integer!")
for i in range(0, max_num):
f = open("Saves.txt", "a")
f.write(write_list[i])
f.close()
os._exit(1)
def main():
store_num_needs = True
while store_num_needs == True:
set_store_num = input("State the current storage amount: \n")
try:
int(set_store_num)
store_num = set_store_num
store_num = int(store_num)
store_num_needs = False
except:
print("It must be an integer!")
try:
f1 = open("Saves.txt", "r")
for i in range(0, store_num+1):
i, = f1.split("#")
f1.close()
except:
print("--------Loading-------")
time.sleep(1)
while True:
os.system("cls")
user_choice = ""
print("Main Menu" + "\n" + "---------")
print("1) Write")
print("2) Read")
print("3) Exit")
while user_choice not in ["1", "2", "3"]:
user_choice = input("Pick 1, 2 or 3 \n")
if user_choice == "1":
write()
elif user_choice == "2":
read()
else:
exit()
if __name__ == "__main__":
main()
It might be too complicated to understand in which case just ask me in comments- otherwise general tips would be nice aswell.
Thanks in advance
A quick point of correction:
global is only required if you're defining a global variable inside a non-global context. In other words, anything defined at the default indentation level, will be accessible by everything else defined below it. For example:
def set_global():
x = 1
def use_global():
x += 1
set_global()
try:
use_global()
except Exception as e:
# `use_global` doesn't know
# about what `set_global` did
print("ERROR: " + str(e))
# to resolve this we can set `x` to a
# default value in a global context:
x = 1
# or, if it were required, we
# could create a global variable
def make_global():
global x
make_global()
# either will work fine
set_global()
use_global()
print(x) # prints 2
Now to the actual question:
I haven't read through the block of code you wrote (probably best to trim it down to just the relevant bits in the future), but this should solve the problem as I understand it, and you described it.
import os
import sys
user_text = []
# login the user somehow
user_file = 'saves.txt'
def writelines(f, lines):
"""Write lines to file with new line characters"""
f.writelines('\n'.join(lines))
def readlines(f):
"""Get lines from file split on new line characters"""
text = f.read()
return text.split('\n') if text else []
class _Choice(object):
"""Class that is equivalent to a set of choices
Example:
>>> class YesObj(Choice):
>>> options = ('y', 'yes')
>>> Yes = YesObj()
>>> assert Yes == 'yes'
>>> assert Yes == 'y'
>>> # assertions evaluate to True
Override the `options` attribute to make use
"""
allowed = ()
def __eq__(self, other):
try:
s = str(other)
except:
raise TypeError("Cannot compare with non-string")
else:
return s.lower() in self.allowed
def _choice_repr(choices):
allowed = []
for c in choices:
if isinstance(c, _Choice):
allowed.extend(c.allowed)
else:
allowed.append(c)
if len(allowed) > 2:
s = ', '.join([repr(c) for c in allowed[:-1]])
s += ', or %s' % repr(allowed[-1])
elif len(allowed) == 1:
s = '%s or %s' % allowed
else:
s = '%s' % allowed[0]
return s
def _choice_sentinel(name, allowed):
"""Creates a sentinel for comparing options"""
return type(name, (_Choice,), {'allowed': list(allowed)})()
Quit = _choice_sentinel('Quit', ('q', 'quit'))
Yes = _choice_sentinel('Yes', ('y', 'yes'))
No = _choice_sentinel('No', ('n', 'no'))
def readline_generator(f):
"""Generate a file's lines one at a time"""
t = f.readline()
# while the line isn't empty
while bool(t):
yield t
t = f.readline()
def read_from_cache():
"""Overwrite `user_text` with file content"""
if not os.path.isfile(user_file):
open(user_file, 'w').close()
globals()['user_text'] = []
else:
with open(user_file, 'r') as f:
lines = readlines(f)
# replace vs extend user text
for i, t in enumerate(lines):
if i == len(user_text):
user_text.extend(lines[i:])
else:
user_text[i] = t
def write_to_cache():
"""Overwrite cache after the first line disagrees with current text
If modifications have been made near the end of the file, this will
be more efficient than a blindly overwriting the cache."""
with open(user_file, 'r+') as f:
i = -1
last_pos = f.tell()
# enumerate is a generator, not complete list
for i, t in enumerate(readline_generator(f)):
if user_text[i] != t:
# rewind to the line before
# this diff was encountered
f.seek(last_pos)
# set the index back one in
# order to catch the change
i -= 1
break
last_pos = f.tell()
# then cut off remainder of file
f.truncate()
# recall that i is the index of the diff
# replace the rest of it with new
# (and potentially old) content
writelines(f, user_text[i+1:])
def blind_write_to_cache():
"""Blindly overwrite the cache with current text"""
with open(user_file, 'w') as f:
writelines(f, user_text)
def overwrite_user_text(i, text, save=False):
"""Overwrite a line of text
If `save` is True, then these changes are cached
"""
try:
user_text[i] = text
except IndexError:
raise IndexError("No text exists on line %r" % (i+1))
if save:
write_to_cache()
def user_input():
"""Get a new line from the user"""
return raw_input("input text: ")
def user_choice(msg, choices):
if len(choices) == 0:
raise ValueError("No choices were given")
ans = raw_input(msg)
if ans not in choices:
print("Invalid Response: '%s'" % ans)
m = "Respond with %s: " % _choice_repr(choices)
return user_choice(m, choices)
else:
return ans
def user_appends():
"""User adds a new line"""
user_text.append(user_input())
def user_reads(*args, **kwargs):
"""Print a set of lines for the user
Selects text via `user_text[slice(*args)]`
Use 'print_init' in kwargs to choose how
many lines are printed out before user must
scroll by pressing enter, or quit with 'q'."""
print_init = kwargs.get('print_init', 4)
sliced = user_text[slice(*args)]
if not isinstance(sliced, list):
sliced = [sliced]
for i, l in enumerate(sliced):
if i < print_init:
print(l)
sys.stdout.flush()
elif user_choice(l, ['', Quit]) == Quit:
break
def user_changes(i=None, save=False):
"""User changes a preexisting line"""
attempt = True
while i is None and attempt:
# get the line the user wants to change
i_text = raw_input("Line to be changed: ")
try:
# make user input an index
i = int(i_text)
except:
# check if they want to try again
c = user_choice("Bad input - '%s' is not an "
"integer. Try again? " % i_text, (Yes, No))
attempt = (c == Yes)
if attempt:
# user gave a valid integer for indexing
try:
user_reads(i-1)
overwrite_user_text(i-1, user_input(), save)
except Exception as e:
print("ERROR: %s" % e)
if user_choice("Try again? ", (Yes, No)):
user_changes(i, save)
# stores whatever text is already on
# file to `user_text` before use
read_from_cache()