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append text from input without changing previous text in python

i want to make python create a file if it doesn't exist ,then take text from users input and append into my file and to be able to use my code several times without changing text before it
def register():
f=open('1.txt','w')
f=open('1.txt','r')
users=f.readlines()
f=open('1.txt','a')
while True:
username = input('Enter your username: ')
password = input('Enter your password: ')
if username in users:
print('this username is taken')
else:
f.write(f'{username}\n')
f.write(f'{password}')
break
this is my code

EAFP approach (which is more pythonic that LBYL):
try to create a file
handle specific exception if it exists
either way do your logic in finally block
try:
with open("1.txt","x") as f: pass
except FileExistsError:
print("File already exists!")
finally:
with open("1.txt", "r+") as f:
lines = f.readlines()
username, password = input("Type username and password (separated by a space): ").split()
if f"{username}\n" in lines:
print('This username is taken!')
else:
f.writelines([f"{username}\n",f"{password}\n"])
Keep in mind though that:
if the username and password are the same this won't work correctly (or at least not as expected imho, as homework figure out why :D )
passwords in general should NOT be kept as plain text
you should add the "boilerplate" if __name__=="__main__": thingy if it's a standalone and no part of a function/class etc
you could wrap the input in try...except ValueError block to be extra safe when somebody enters a single value or three values and so on
Comments:
If you do something like this:
f=open('1.txt','w')
f=open('1.txt','r')
The 2nd line shadows the first one, so it makes no sense, it's the same as:
x=2
x=3
print(x)
The 1st assignment is "dead"
Most often you want to use with when handling files operations, otherwise it's your responsibility to close the file as well.

How to save output in python to .txt file

So basically i bought a book that teaches the basics of python and how to create a random number generator so I decided to go one step further and make a random password generator I found a tutorial online that gave me a good example of why and what is used to make a password generator but i want the output to be saved to a .txt file I do not know what i need to implement to get the result i want this is what i have i'm using python3.
import random
chars = 'abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ!, #,#$%^&*.'
number = input('Number of passwords - ')
number = int(number)
length = input('password length? - ')
length = int(length)
answer = input
for P in range(number):
password = ''
for C in range(length):
password += random.choice(chars)
print(password)
password = open("passlist.txt", "a")
password.write(password)
password.close()
file = open('passlist', 'w')
file.write(password)
file.close()
this is what i get in shell
Traceback (most recent call last):
File "C:\User\Desktop\passgen.py", line 21, in <module>
password.write(password)
TypeError: write() argument must be str, not _io.TextIOWrapper

When you open a new file and set it equal to a variable, you are actually creating an _io.TextIOWrapper object. So in this line of code, you are creating this object and storing it in password, getting rid of the password generated in the previous lines of code.
password = open("passlist.txt", "a")
You are then trying to write to the passlist.txt file with this line:
password.write(password)
You are telling password, now an _io.TextIOWrapper object, to write to the passfile.txt the _io.TextIOWrapper object, not the password generated beforehand. This function is expecting a string, and you are now passing an _io.TextIOWrapper object. Since password is no longer a string, that is why you are running into the error.
To fix this, I would suggest creating a new variable:
txtFileWriter = open("passlist.txt", "a")
txtFileWriter.write(password)
txtFileWriter.close()
You may find that after fixing this, only one value is being stored inside your text file. I would recommend properly nesting your for loops:
for P in range(number):
password = ''
for C in range(length):
password += random.choice(chars)
print(password)
The meaning of these for loops can be translated as:
For each password, set the password = ' ' and for each character, add one random character to password.
The problem with this is that you will only have one password after the for loops are complete. You are setting the password value to ' ' each time you run through the outer loop. The only password that will be saved, will be the last value. In order to fix this, I recommend using a list.
I recommend reading through this documentation
I don't want to spoon feed the answers since I realize you are learning python, so I will leave it here. You will want to create a list and then append a value to that list each time you generate a password. After some reading, hopefully this will make sense.

filename = 'passlist.txt'
with open (filename, 'a') as file_object:
file_object.write(password)
Using with will close the file once access is no longer needed.
You also need a list to append your passwords ;)

The error originates from password being re-assigned in password = open("passlist.txt", "a"). This causes and error in the next line as you are attempting to pass password as parameter to itself in password.write(password).
Some farther assistance
You have the right idea but you forgot to indent. All the lines below for P in range(number): should be indented because the program must generate and write a new password until it has satisfied the required amount of passwords.
The password = open("passlist.txt", "a")
password.write(password)
password.close() lines are unnecessary as you are overriding the generated password and assigning that password variable to something that is not a string; that is why you are getting that error.
Here is the code with the adjustments.
import random
chars = 'abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ!, #,#$%^&*.'
number = input('Number of passwords - ')
number = int(number)
length = input('password length? - ')
length = int(length)
answer = input
for P in range(number):
password = ''
for C in range(length):
password += random.choice(chars)
print(password)
password += "\n" # writes the password in a new line
file = open('passlist.tx', "a")
file.write(password)
file.close()

Simple Python Excel password crack - Brute Force

For a demonstration I want to crack an excel file (named 'xl') password. I use the following code but (1) it fails to open excel and (2) it does not stop running when the password is cracked.
import itertools
import string
from win32com.client import Dispatch
file = input('Path: ')
chars = string.ascii_lowercase + string.digits
for password_length in range(1, 2):
for password in itertools.product(chars, repeat=password_length):
password = ''.join(password)
print ('Testing password: '+ password)
instance = Dispatch ('Excel.Application')
try:
instance.Workbooks.Open(file, False, True, None, password)
print ('Password Cracked: ' + password)
#break
except:
pass
I set the excel password as 'p' and the code just runs through 1 character combinations for simplicity. Moreover, when you run the code it requires as input the path of the excel file.
I can't figure out my mistake and I would appreciate some help. Also if doing this for a word document is easier please let me know.

Loop does not stop because you have #break commented out.

Checking if a string is in a file

I am making a program that checks to see if any of the user's input is in the file. If the user input is not currently in the file, then we will append that input into the used_passwords file and ask the user to type something else again. else if they retype the input we just recently added(or any of the presets) then we want to tell them that they can't reuse a password.
The problem I am having with this code is that whenever I type a letter that is from the word in the used_passwords file or if I type a part of the word in the file then the program tells me that I can't reuse a password.
For example: If I type in "abc", the program will tell me that I have already reused that password and I am assuming it is probably because the program reads the files character by character and reads the abc in abcdeF!23.
Although, I don't want the program to tell me I can't reuse a or multiple characters from the file. I want the program to tell me that I can't reuse a word from the program
I am also wondering if we could put the inputs or presets into an array IN THE FILE.
fileUsed_Pass = open("used_passwords.txt", 'a')
fileUsed_Pass.write("\nabcdeF!23")
fileUsed_Pass.write("\n\n")
fileUsed_Pass.write("zxcbhK#44")
fileUsed_Pass.write("\n\n")
fileUsed_Pass.write("poiuyT&11")
fileUsed_Pass.write("\n\n")
fileUsed_Pass.close()
def password():
string = input("Enter Here:")
if string in open('used_passwords.txt').read():
print("You can not reuse that password!\n")
password()
else:
# file-append.py
f = open('used_passwords.txt','a')
f.write('\n'+string)
f.close()
password()
password()
UPDATE: I have gotten the code to work using the with statement.
rather than using an If and else statement, I had used a with statement.
Here what I am doing is checking for every single line to see if it has any text that matches my input string. If there are none, then we'll make some_variable equal True. If it doesn't, then we'll make it equal false.
with open("used_passwords.txt", 'r') as tFile:
for line in tFile:
if string != line and string+"\n" != line:
some_variable = True
else: #If it equals anything else from the file, then false
some_variable = False
break
#print(some_variable)
#this was added for me/the user to make sure that the with statement was working
Afterwards, if it does equal True: we'll add it to the file. If it doesn't we'll make the user input another password that does not match any of the ones insie of the file.
tFile = open("used_passwords.txt", 'a')
if some_variable == True:
tFile.write("\n" + string)
print("\nGOOD! Password does not match old ones!")
elif some_variable == False:
print("\nYou can not re-use a password!")
password()

Working directly with text files is probably not the greatest solution;
you should consider using some form of database instead (such as the sqlite3 library which, IIRC, comes preinstalled with Python3).
Also, keep in mind that storing passwords as clear text is a security "no-no".
At the very least, use one of the many available cryptographic hash functions, then store and compare the hashes, not the passwords.
Here's a basic example that uses both sqlite3 and SHA-256, a common hashing function:
#!/usr/bin/python3
import sqlite3
import hashlib
db = sqlite3.connect( "used_passwords.db" )
cur = db.cursor()
cur.execute( "CREATE TABLE IF NOT EXISTS passwords( pwd TEXT, UNIQUE( pwd ))" )
def password():
pwd = input( "password: " )
sha = hashlib.sha256( pwd.encode( 'utf-8' )).hexdigest()
cur.execute( "INSERT INTO passwords VALUES( ? )", ( sha, ))
while True:
try:
password()
break
except KeyboardInterrupt:
print( "aborted" )
break
except sqlite3.IntegrityError:
print( "cannot reuse that password" )
db.commit()
db.close()
Note the UNIQUE constraint on pwd, which ensures that an sqlite3.IntegrityError exception is raised whenever a password is already present in passwords (this makes the verification implicit, and minimizes the SQL cumbersomeness).
Usage example:
% ./pwd.py
password: foo
% ./pwd.py
password: foo
cannot reuse that password
password: bar
%
You can verify that no clear-text password appears in the database:
% sqlite3 ./used_passwords.db
SQLite version 3.16.2 2017-01-06 16:32:41
Enter ".help" for usage hints.
sqlite> select * from passwords;
2c26b46b68ffc68ff99b453c1d30413413422d706483bfa0f98a5e886266e7ae ; <- this is "foo"
fcde2b2edba56bf408601fb721fe9b5c338d10ee429ea04fae5511b68fbf8fb9 ; <- this is "bar"
sqlite>
Of course you can expand on that and add more features, such as support for multiple users, password expiration, etc...

Considering that you are adding a \n after each password you enter in the file, you can try to append \n to the string variable and then search after that.

You're using .read(), which reads the entire file as one string.
word = 'abc'
for line in open('file.txt').readlines():
if word in line:
return True
Use .readlines() instead and loop through every line to check if the string is in any of the file lines.

txt file to dictionary and login implementation Python 3

I am attempting to create a login script. I have the usernames and passwords in a text file that I want python to read and check through to find usernames and passwords.
The biggest problem I am having is "attaching" the password to a username. I can currently only scan the whole of the document for both but not necessarily attached to each other.
#-------------------------------------------------------------------------------
# Name: LogIn
# Purpose: Logging In
#
# Author: Dark Ariel7
#
# Created: 19/02/2013
# Copyright: (c) Dark Ariel7 2013
# Licence: I take no responsability for anything.
#-------------------------------------------------------------------------------
from getpass import getpass
from time import sleep
Database = open("C:\\Users\Dark Ariel7\\Desktop\\USB BAckup\\Scripts\\Database.txt", encoding='utf-8')
Username = ("")
Password = ()
def LogIn():
Database = open("C:\\Users\Dark Ariel7\\Desktop\\USB BAckup\\Scripts\\Database.txt", encoding='utf-8')
Data = (Database.read())
Username = ("")
Password = ()
Username = input("Username: ")
Password = getpass(str("Password: "))
LogIn= ",".join((Username,Password))
if LogIn in Data:
print("Welcome, " + Username)
sleep(3)
pass
else:
print("Failed, Sucker!")
sleep(5)
exit()
LogIn()
If you guys could help me figure out what exactly .join part is for that would be great. Should i make a dictionary and use the index for a login sheet? I also want some general feedback on how to make the code better.
This is the txt file that it will be reading:
[Dark Ariel7,123456]
[Poop,Anko]
*Edit Sorry guys I forgot to mention that I am using python 3 not 2. Thanks so far. Very quick replies. Also after the last else instead of exit what do I put so that the function loops until I get the right username password combo?

The ".join" part joins the username and password that the user types in with a comma between them (i.e. Poop,Anko) because that's the format in which it's stored in the database, so you can search for it that way.
Here's your code, edited up a bit, with some comments about functionality and style.
from getpass import getpass
from time import sleep
Database = open("C:\\Users\Dark Ariel7\\Desktop\\USB BAckup\\Scripts\\Database.txt", encoding='utf-8')
# These next two lines aren't necessary - these variables are never used; you may want to read up about namespaces: http://bytebaker.com/2008/07/30/python-namespaces/
#Username = ("")
#Password = ()
def LogIn():
Database = open("C:\\Users\Dark Ariel7\\Desktop\\USB BAckup\\Scripts\\Database.txt", encoding='utf-8')
# Removed the parentheses; they have no effect here. Putting parens around lone statements doesn't have any effect in python.
Data = Database.read()
# These next two lines are pointless, because you subsequently overwrite the values you give these variables. It looks like you're trying to "declare" variables, as you would in Java, but this isn't necessary in python.
# Username = ("")
# Password = ()
# Changed this from "input" to "raw_input" because input does something else that you don't want.
Username = raw_input("Username: ")
Password = getpass(str("Password: "))
LogIn= ",".join((Username,Password))
if LogIn in Data:
print("Welcome, " + Username)
# Not sure why you want the script to sleep, but I assume you have your reasons?
sleep(3)
# no need to pass
# pass
else:
print("Failed, Sucker!")
sleep(5)
# exit() isn't necessary - the function will end by itself.
# exit()
LogIn()

The basic problem you have is that your file has [ ] surrounding the username and password combination, but you fail to account for this.
There are some other stylistic issues with your code, here is an edited version:
import getpass
from time import sleep
password_file = r'C:\....\Database.txt'
def login(user,passwd):
''' Checks the credentials of a user '''
with open(password_file) as f:
for line in f:
if line.strip(): # skips blank lines
username,password = line.split(',') # this gets the individual parts
username = username[1:] # gets rid of the [
password = password[:-1] # the same for the password
if user == username and password == passwd:
return True
return False
if __name__ == '__main__':
username = input('Please enter the username: ')
passwd = getpass('Please enter the password: ')
if login(user,passwd):
print('Welcome {1}'.format(user))
sleep(3)
else:
print('Failed! Mwahahaha!!')
sleep(5)
To start off with, you don't need () to "initialize" variables; more to the point in Python you don't need to initialize variables at all. This is because Python doesn't have variables; but rather names that point to things.
Next, the python style guide says that variable names should be lowercase, along with method names.
Now - the main part of the code:
>>> username, password = '[username,sekret]'.split(',')
>>> username
'[username'
>>> password
'sekret]'
I used split() to break up the line into the username and password parts; but as you see there is still the [ messing things up. Next I did this:
>>> username[1:]
'username'
>>> password[:-1]
'sekret'
This uses the slice notation to strip of the leading and ending characters, getting rid of the [ ].
These lines:
with open(password_file) as f: # 1
for line in f: # 2
if line.strip(): # skips blank lines
Do the following:
Opens the file and assigns it to the variable f (see more on the with statement)
This for loop steps through each line in f and assigns the name line to each line from the file.
The third part makes sure we skip blank lines. strip() will remove all non-printable characters; so if there are no characters left, the line is blank and will have a 0 length. Since if loops only work when the condition is true, and 0 is a false value - in effect what happens is we only operate on non-blank lines.
The final part of the code is another if statement. This is a check to make sure that the file will run when you execute it from the command prompt.