Program that Encrypts and Decrypts a text file - python

My sample text file is: 'abcd abcd abcd'
The program has a dictionary with symbols dedicated for each letter. The objective is to create a new file with the files message encrypted.
Program 'works'. By this I mean that it only converts abc. Since theres no d in the dictionary then it raises an error. I removed the d and tried again, but this raises another error called: KeyError: ' '
How can I make my program detect spaces, and write the letter even if theres no symbol for it?
def main():
ecrypt = {'a':'%', 'b':'&', 'c':'/'}
input_file = open('efile.txt', 'r')
output_file = open('newefile.txt', 'w')
line = input_file.readline()
for letter in line:
if letter in line:
output_file.write(ecrypt[letter])
main()

You can use a try-except for handle the KeyError but as a more pythonic way you can use str.translate() function that is actually for this aim :
>>> from string import maketrans
>>> i='abc'
>>> o='%&/'
>>> trantab = maketrans(i, o)
>>> print 'abcd abcd abcd'.translate(trantab)
%&/d %&/d %&/d
and for translate the file and write in another file :
from string import maketrans
i='abc'
o='%&/'
trantab = maketrans(i, o)
with open('efile.txt', 'r') as infile,open('newefile.txt', 'w') as out :
out.write(infile.read().translate(trantab))

You're trying to access ecrypt['d'] which doesn't exist. With this current code, you'd need to make sure every character (not just letter, punctuation... Spaces...) is in the ecrypt dict.
I suggest adding an exception. See https://docs.python.org/2/tutorial/errors.html
The 'if letter in line' is superfluous.
for letter in line:
try:
output_file.write(ecrypt[letter])
except KeyError:
output_file.write(letter)
Or, test that the letter exists first.
for letter in line:
cipher_letter=ecrypt[letter] if letter in ecrypt else letter
output_file.write(cipher_letter)

Related

How can I get pyautogui to print words from a string?

I'm working on a project which I want to be able to take words separated by a space, turn it into a string using .split() and then have pyautogui print it out with an "enter" being pressed in between each word. This is the code I have so far below.
# Importing stuff
import pyautogui
# Configure Typing Thing
pyautogui.PAUSE = 0
# Input
input = "hi this is a test run of this program"
# generate words
output_list = input.split()
pyautogui.write(output_list)
pyautogui.press("enter")
Could someone tell me what I did wrong while writing this? Thanks in advance.
Try this:
import pyautogui
pyautogui.PAUSE = 0
input = "hi this is a test run of this program"
output_list = input.split()
for x in output_list:
pyautogui.write(x)
pyautogui.press("enter")
You probably should not use the word input as a variable name as it is a builtin function in Python. To print the words with an enter between them use the following code:
ipt = "hi this is a test run of this program"
ipt = ipt.split()
for word in ipt:
pyautogui.write(word + "\n")
The "\n" is interpreted as a new line character and therefore the write function prints it as a new line (aka an enter)
EDIT: Even easier is something where you replace every space in the string with a newline character and then write that. For example:
ipt = "hi this is a test run of this program"
ipt = ipt.replace(" ", "\n")
pyautogui.write(ipt)

Read Null terminated string in python

I'm trying to read a null terminated string but i'm having issues when unpacking a char and putting it together with a string.
This is the code:
def readString(f):
str = ''
while True:
char = readChar(f)
str = str.join(char)
if (hex(ord(char))) == '0x0':
break
return str
def readChar(f):
char = unpack('c',f.read(1))[0]
return char
Now this is giving me this error:
TypeError: sequence item 0: expected str instance, int found
I'm also trying the following:
char = unpack('c',f.read(1)).decode("ascii")
But it throws me:
AttributeError: 'tuple' object has no attribute 'decode'
I don't even know how to read the chars and add it to the string, Is there any proper way to do this?
Here's a version that (ab)uses __iter__'s lesser-known "sentinel" argument:
with open('file.txt', 'rb') as f:
val = ''.join(iter(lambda: f.read(1).decode('ascii'), '\x00'))
How about:
myString = myNullTerminatedString.split("\x00")[0]
For example:
myNullTerminatedString = "hello world\x00\x00\x00\x00\x00\x00"
myString = myNullTerminatedString.split("\x00")[0]
print(myString) # "hello world"
This works by splitting the string on the null character. Since the string should terminate at the first null character, we simply grab the first item in the list after splitting. split will return a list of one item if the delimiter doesn't exist, so it still works even if there's no null terminator at all.
It also will work with byte strings:
myByteString = b'hello world\x00'
myStr = myByteString.split(b'\x00')[0].decode('ascii') # "hello world" as normal string
If you're reading from a file, you can do a relatively larger read - estimate how much you'll need to read to find your null string. This is a lot faster than reading byte-by-byte. For example:
resultingStr = ''
while True:
buf = f.read(512)
resultingStr += buf
if len(buf)==0: break
if (b"\x00" in resultingStr):
extraBytes = resultingStr.index(b"\x00")
resultingStr = resultingStr.split(b"\x00")[0]
break
# now "resultingStr" contains the string
f.seek(0 - extraBytes,1) # seek backwards by the number of bytes, now the pointer will be on the null byte in the file
# or f.seek(1 - extraBytes,1) to skip the null byte in the file
(edit version 2, added extra way at the end)
Maybe there are some libraries out there that can help you with this, but as I don't know about them lets attack the problem at hand with what we know.
In python 2 bytes and string are basically the same thing, that change in python 3 where string is what in py2 is unicode and bytes is its own separate type, which mean that you don't need to define a read char if you are in py2 as no extra work is required, so I don't think you need that unpack function for this particular case, with that in mind lets define the new readString
def readString(myfile):
chars = []
while True:
c = myfile.read(1)
if c == chr(0):
return "".join(chars)
chars.append(c)
just like with your code I read a character one at the time but I instead save them in a list, the reason is that string are immutable so doing str+=char result in unnecessary copies; and when I find the null character return the join string. And chr is the inverse of ord, it will give you the character given its ascii value. This will exclude the null character, if its needed just move the appending...
Now lets test it with your sample file
for instance lets try to read "Sword_Wea_Dummy" from it
with open("sword.blendscn","rb") as archi:
#lets simulate that some prior processing was made by
#moving the pointer of the file
archi.seek(6)
string=readString(archi)
print "string repr:", repr(string)
print "string:", string
print ""
#and the rest of the file is there waiting to be processed
print "rest of the file: ", repr(archi.read())
and this is the output
string repr: 'Sword_Wea_Dummy'
string: Sword_Wea_Dummy
rest of the file: '\xcd\xcc\xcc=p=\x8a4:\xa66\xbfJ\x15\xc6=\x00\x00\x00\x00\xeaQ8?\x9e\x8d\x874$-i\xb3\x00\x00\x00\x00\x9b\xc6\xaa2K\x15\xc6=;\xa66?\x00\x00\x00\x00\xb8\x88\xbf#\x0e\xf3\xb1#ITuB\x00\x00\x80?\xcd\xcc\xcc=\x00\x00\x00\x00\xcd\xccL>'
other tests
>>> with open("sword.blendscn","rb") as archi:
print readString(archi)
print readString(archi)
print readString(archi)
sword
Sword_Wea_Dummy
ÍÌÌ=p=Š4:¦6¿JÆ=
>>> with open("sword.blendscn","rb") as archi:
print repr(readString(archi))
print repr(readString(archi))
print repr(readString(archi))
'sword'
'Sword_Wea_Dummy'
'\xcd\xcc\xcc=p=\x8a4:\xa66\xbfJ\x15\xc6='
>>>
Now that I think about it, you mention that the data portion is of fixed size, if that is true for all files and the structure on all of them is as follow
[unknow size data][know size data]
then that is a pattern we can exploit, we only need to know the size of the file and we can get both part smoothly as follow
import os
def getDataPair(filename,knowSize):
size = os.path.getsize(filename)
with open(filename, "rb") as archi:
unknown = archi.read(size-knowSize)
know = archi.read()
return unknown, know
and by knowing the size of the data portion, its use is simple (which I get by playing with the prior example)
>>> strins_data, data = getDataPair("sword.blendscn", 80)
>>> string_data, data = getDataPair("sword.blendscn", 80)
>>> string_data
'sword\x00Sword_Wea_Dummy\x00'
>>> data
'\xcd\xcc\xcc=p=\x8a4:\xa66\xbfJ\x15\xc6=\x00\x00\x00\x00\xeaQ8?\x9e\x8d\x874$-i\xb3\x00\x00\x00\x00\x9b\xc6\xaa2K\x15\xc6=;\xa66?\x00\x00\x00\x00\xb8\x88\xbf#\x0e\xf3\xb1#ITuB\x00\x00\x80?\xcd\xcc\xcc=\x00\x00\x00\x00\xcd\xccL>'
>>> string_data.split(chr(0))
['sword', 'Sword_Wea_Dummy', '']
>>>
Now to get each string a simple split will suffice and you can pass the rest of the file contained in data to the appropriated function to be processed
Doing file I/O one character at a time is horribly slow.
Instead use readline0, now on pypi: https://pypi.org/project/readline0/ . Or something like it.
In 3.x, there's a "newline" argument to open, but it doesn't appear to be as flexible as readline0.
Here is my implementation:
import struct
def read_null_str(f):
r_str = ""
while 1:
back_offset = f.tell()
try:
r_char = struct.unpack("c", f.read(1))[0].decode("utf8")
except:
f.seek(back_offset)
temp_char = struct.unpack("<H", f.read(2))[0]
r_char = chr(temp_char)
if ord(r_char) == 0:
return r_str
else:
r_str += r_char

Python - How to make sure that a line being read from a file contain only a given string and nothing else

In order to make sure I start and stop reading a text file exactly where I want to, I am providing 'start1'<->'end1', 'start2'<->'end2' as tags in between the text file and providing that to my python script. In my script I read it as:
start_end = ['start1','end1']
line_num = []
with open(file_path) as fp1:
for num, line in enumerate(fp1, 1):
for i in start_end:
if i in line:
line_num.append(num)
fp1.close()
print '\nLine number: ', line_num
fp2 = open(file_path)
for k, line2 in enumerate(fp2):
for x in range(line_num[0], line_num[1] - 1):
if k == x:
header.append(line2)
fp2.close()
This works well until I reach start10 <-> end10 and further. Eg. it checks if I have "start2" in the line and also reads the text that has "start21" and similarly for end tag as well. so providing "start1, end1" as input also reads "start10, end10". If I replace the line:
if i in line:
with
if i == line:
it throws an error.
How can I make sure that the script reads the line that contains ONLY "start1" and not "start10"?
import re
prog = re.compile('start1$')
if prog.match(line):
print line
That should return None if there is no match and return a regex match object if the line matches the compiled regex. The '$' at the end of the regex says that's the end of the line, so 'start1' works but 'start10' doesn't.
or another way..
def test(line):
import re
prog = re.compile('start1$')
return prog.match(line) != None
> test('start1')
True
> test('start10')
False
Since your markers are always at the end of the line, change:
start_end = ['start1','end1']
to:
start_end = ['start1\n','end1\n']
You probably want to look into regular expressions. The Python re library has some good regex tools. It would let you define a string to compare your line to and it has the ability to check for start and end of lines.
If you can control the input file, consider adding an underscore (or any non-number character) to the end of each tag.
'start1_'<->'end1_'
'start10_'<->'end10_'
The regular expression solution presented in other answers is more elegant, but requires using regular expressions.
You can do this with find():
for num, line in enumerate(fp1, 1):
for i in start_end:
if i in line:
# make sure the next char isn't '0'
if line[line.find(i)+len(i)] != '0':
line_num.append(num)

re.match doesn't pick up on txt file format

import os.path
import re
def request ():
print ("What file should I write to?")
file = input ()
thing = os.path.exists (file)
if thing == True:
start = 0
elif re.match ("^.+.\txt$", file):
stuff = open (file, "w")
stuff.write ("Some text.")
stuff.close ()
start = 0
else:
start = 1
go = "yes"
list1 = (start, file, go)
return list1
start = 1
while start == 1:
list1 = request ()
(start, file, go) = list1
Whenever I enter Thing.txt as the text, the elif should catch that it's in the format given. However, start doesn't change to 0, and a file isn't created. Have I formatted the re.match incorrectly?
"^.+.\txt$" is an incorrect pattern for match .txt files you can use the following regex :
r'^\w+\.txt$'
As \w matches word character if you want that the file name only contain letters you could use [a-zA-Z] instead :
r'^[a-zA-Z]+\.txt$'
Note that you need to escape the . as is a special sign in regular expression .
re.match (r'^\w+\.txt$',file)
But as an alternative answer for match file names with special format you can use endswith() :
file.endswith('.txt')
Also instead of if thing == True you can just use if thing : that is more pythonic !
You should escape second dot and unescape the "t" character:
re.match ("^.+\.txt$", file)
Also note that you don't really need regex for this, you can simply use endswith or search for module that can give you files extensions:
import os
fileName, fileExtension = os.path.splitext('your_file.txt')
fileExtension is .txt, which is exactly what you're looking for.

How can i write this function that mostly prints to a file?

So I posted about another part of this code yesterday but I've run into another problem. I made a character generator for an RPG and im trying to get the program the output of a character sheet function to a .txt file, but i think whats happening is that the function may return a Nonevalue for some of the stats (which is totally normal,) and then i get an error because of that when i try to write to a .txt file. I'm totally stumped, and help would be vastly appreciated!
# Character Sheet Function.
def char_shee():
print "Name:", name
print "Class:", character_class
print "Class Powers:", class_power
print "Alignment:", alignment
print "Power:", pow, pow_mod()
print "Intelligence:", iq, iq_mod()
print "Agility:", agi, agi_mod()
print "Constitution:", con, con_mod()
print "Cynicism:", cyn, cyn_mod()
print "Charisma:", cha, cha_mod()
print "All Characters Start With 3 Hit Dice"
print"""
\t\t{0}'s History
\t\t------------------
\t\tAge:{1}
\t\t{2}
\t\t{3}
\t\t{4}
\t\t{5}
\t\t{6}
\t\t{7}
\t\t{8}
\t\t{9}
\t\tGeneral Disposition: {10}
\t\tMost important thing is: {11}
\t\tWho is to blame for worlds problems: {12}
\t\tHow to solve the worlds problems: {13}
""".format(name, age, gender_id, ethnic_pr, fcd, wg, fogo_fuck, cur_fam,fam_fuk, nat_nur, gen_dis, wha_wor, who_pro, how_pro)
char_shee()
print "Press enter to continue"
raw_input()
# Export to text file?
print """Just because I like you, let me know if you want this character
saved to a text file. Please remember if you save your character not to
name it after something important, or you might lose it.
"""
text_file = raw_input("Please type 'y' or 'n', if you want a .txt file")
if text_file == "y":
filename = raw_input("\nWhat are we calling your file, include .txt")
target = open(filename, 'w')
target.write(char_shee()
target.close
print "\nOk I created your file."
print """
Thanks so much for using the Cyberpanky N.O.W Character Generator
By Ray Weiss
Goodbye
"""
else:
print """
Thanks so much for using the Cyberpanky N.O.W Character Generator
By Ray Weiss
Goodbye
"""
EDIT: Here is the output i get:
> Please type 'y' or 'n', if you want a .txt filey
>
> What are we calling your file, include .txt123.txt <function char_shee
> at 0x2ba470> Traceback (most recent call last): File "cncg.py", line
> 595, in <module>
> target.write(pprint(char_shee)) TypeError: must be string or read-only character buffer, not None
Using print writes to sys.stdout, it doesn't return a value.
You you want char_shee to return the character sheet string to write it to a file, you'll need to just build that string instead.
To ease building the string, use a list to collect your strings:
def char_shee():
sheet = []
sheet.append("Name: " + name)
sheet.append("Class: " + character_class)
# ... more appends ...
# Return the string with newlines
return '\n'.join(sheet)
you forgot parenthesis here:
target.write(char_shee())
target.close()
and as #Martijn Pieters pointed out you should return value from char_shee(), instead of printing them.

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