i am learning python, and i wanted to create a little login and register program, that writes the username and the password to a txt file (so that it can be later used), i am currently working on the register function, when i try to write to the txt files it does nothing, i tried doing a with loop, a .flush() and .close() but neither of them saves the info.
Here's my code:
username.write = input ('username > ')
password = open("password.txt", "w")
password.write = input ('password > ')
print('Welcome.')
username.close()
password.close()
What am i missing?
Edit.
Neither 3 of the solutions to the suggested question work for me...
Get your input and store them in two variables and then write them to files:
username = input ('username > ')
password = input ('password > ')
with open('usernames.txt', 'w') as userFile:
userFile.write(username)
with open('passwords.txt', 'w') as passFile:
passFile.write(password)
yourfile.open(filename,'w')
username = input()
password = input()
yourfile.write(username)
yourfile.write(password)
yourfile.close()
I'm learning python and trying to delete the contents of a life after the user input. for some reason it deletes the contents of the .txt before it asks for user input. Can't seem to work it out.
from sys import argv
import sys
script, filename = argv
def erase_contents(f):
user_input = input("> ")
if user_input == "yes":
current_file.truncate()
print("successfully deleted")
else:
sys.exit()
current_file = open(filename, "w+")
print(f"Now we are going to erase the contents of {filename}. type yes to delete.")
erase_contents(current_file)
You don't need to use truncate, because you are opening the file using w+ as the mode, which truncates the file immediately. You could use mode a instead, but really, there's no need to open the file at all until you determine that the user wants to truncate the file. You could just write
def erase_contents(fname):
user_input = input("> ")
if user_input == "yes":
with open(fname, "w"):
pass
else:
sys.exit()
print(f"Now we are going to erase the contents of {filename}. type yes to delete.")
erase_contents(filename)
I am just a beginner to programming and below is the code that I have written in python to save and edit a file but every time I run the programme it erases the previous save data, so I am confused why it's happening?
filename = raw_input("Please enter the file name to open it:\n")
doc = open (filename,'w')
print doc.read
text_input = raw_input("Please enter the data you want to enter in file:\n")
if text_input == "":
print "no input closing the programme."
else :
doc.write(text_input)
doc.close()
print "Printing the file:\n"
print doc.read
cl_file = raw_input("do you want to truncate file(y/n): ")
if cl_file == "y":
doc.truncate()
else :
print "Wrong input closing notepad"
exit()
You are opening the file in write mode, which truncates the file before writing to it. Instead of using open(filename, 'w') use open(filename, 'a'). The 'a' value tells the open function to use append mode so that writes to the file are added to the end of any existing content.
file=open('ClassA1.txt','a')
file=open('ClassB1.txt','a')
file=open('ClassC1.txt','a')
print('hello welcome to maths 2000')
Class=input('please enter your class '+"\n")
name=input('please enter your name '+"\n")
if Class==(int(input"A1")):
file.close('ClassB1')
file.close('ClassC1')
file.write(name+"/n")
file.close
How do I get it to check user input so it can close the files?
Ok first point :
This line:
file=open('ClassA1.txt','a')
opens file 'ClassA1.txt' for appending, assign the file object to the name file (which eventually shadows the builtin type file but that's not relevant here)
Then the second line:
file=open('ClassB1.txt','a')
opens file 'ClassB1.txt' for appending, assign the file object to the name file, sus replacing the binding to the previously opened file "ClassA1.txt". Since there's no other name referencing this previously opened file, it's lost. In the best case, the underlying file pointer will be closed when the object gets garbage-collected (CPython) but this is NOT garanteed by thye language's specification and another implementation might not free the file pointer correctly.
In all cases you can not access 'ClassA1.txt' anymore at this point.
Now the third line:
file=open('ClassC1.txt','a')
does the same thing - reassigning the name file to a new file object etc.
At this point, you have to possibly opened, possibly not, and in both case unreachable (and possibly already garbage collected) file objects and the name file points to the third one - which means any write operation on file will write to file "ClassC1.txt".
If you want to keep all three files opened, you have to keep references to them, either by binding each to a distinct name, ie:
file1=open('ClassA1.txt','a')
file2=open('ClassB1.txt','a')
file3=open('ClassC1.txt','a')
or by storing them in a list:
files = []
files.append(open('ClassA1.txt','a'))
files.append(open('ClassB1.txt','a'))
files.append(open('ClassC1.txt','a'))
so you can now acces them by index, ie files[0], files[1], files[2]
or in a dict:
files = {}
files["A1"] = open('ClassA1.txt','a')
files["B1"] = open('ClassB1.txt','a')
files["C1"] = open('ClassC1.txt','a')
so you can now acces them by key, ie files["A1"], files["A2"], files["A3"]
BUT : why would you
open three files,
ask the user which file he wants to write to,
close the two other files,
write to the selected file
close it
when you could more simply:
ask the user which file he wants to write to,
open it
write to it
close it
Since your files are named after the class name, you can easily build the filename from the class name:
cls = input("please enter your class\n")
filename = "Class{}.txt".format(cls)
f = open(filename, "a")
f.write("whatever")
f.close()
or even more safely (this will ensure the file WILL be closed whatever happens):
cls = input("please enter your class\n")
filename = "Class{}.txt".format(cls)
with open(filename, "a") as f:
f.write("whatever")
Note that in this case you don't have to call f.close()
A couple other points:
Class=input('please enter your class '+"\n")
=> 'cls' or 'class_', not 'Class' - by convention, capitalized names are for class (in the OO meaning) names.
=> Python is not PHP: 'please enter your class \n' just works
if Class==(int(input"A1"))
I don't know what you expect this line to do, but it sure looks you don't know either... One thing is sure : a string won't be equal to an integer. Never...
file.close('ClassB1')
Have you read the documentation at all ? It's here (well, for a starter at least) : https://docs.python.org/3/tutorial/inputoutput.html#reading-and-writing-files
file.close
You want file.close() here. The parens are NOT optional - if you want to call the method at least.
You're doing a long winded way, you could just open the file after the user gives their answer.
import os
print('hello welcome to maths 2000')
yourClass=input('please enter your class '+"\n")
filename = 'Class{}.txt'.format(yourClass)
name=input('please enter your name '+"\n")
if os.path.exists(filename):
f = open(filename, 'a')
file.write(name+"/n")
file.close()
else:
print ("Class not found")
I just set it up so the input determines the filename it tries to open, and if that file exists it opens it and appends their name.
When you execute these
file=open('ClassA1.txt','a')
file=open('ClassB1.txt','a')
file=open('ClassC1.txt','a')
file variable contains "ClassC1.txt", you are re-assigning the object again and again.
so after whatever check if you execute this:
file.close()
last file will be closed.
Instead I would recommend you first take the input of what file is to be opened and then open that file.
file_name = input("Enter file name")
file = open(file_name, 'a')
#do your work
file.close()
fd = open("Student_info.txt", "a+")
class_info = []
print "Hello, welcome to maths 2000"
class_to_be = raw_input("Please enter your class: ")
name = raw_input("Please enter your name: ")
student = name + " " + class_to_be
class_info.append(student)
print class_info
for students in class_info:
fd.write("%s" %(students))
fd.close()
results:
jester112358#ubuntu:~$ python stackhelp.py
Hello, welcome to maths 2000
Please enter your class: Python-class
Please enter your name: Greenie245
['Greenie245 Python-class']
and writes the content of your list to Student_info.txt
I think it's better to have all the information in one file, but obviously you can have a file for every class if you want.
If you want class for every file, consider using:
for students in class_info:
spl = students.split()
if spl[1] == "A1":
A1=open('ClassA1.txt','a')
A1.write("%s" %(students))
A1.write("\n")
A1.close()
elif ... # add anothor classes here
I am working on a Lists, Tuples, and Statistics Program for my intro class, and am having some difficulty with a try-except block. The program we are supposed to make is supposed to ask for the user to name a file to input, and then give some information about the numbers in that file. I have all of the information displays working correctly, but can't write the try-except block. The program needs to accept only the file name "new_numbers.txt" and nothing else.
Here is the top portion of my code:
def main():
#Get the name of the file from the user
while(True):
try:
input("Enter the name of the file you would like to open: ")
except ValueError:
print("That file does not exist. Please enter a valid file.")
break
You need to assign the value from input, and try to open it to see if the file in question is around...:
def main():
#Get the name of the file from the user
while(True):
try:
fn = input('Enter the name of the file you would like to open: ')
f = open(fn)
except IOError:
print('File {} does not exist. Please enter a valid file.'.format(fn))
else:
break
Also note that you should break only when there is no more error; and in that case the open file object is ready as variable f.