Break outside the loop - python

I am new to Python. I am trying to run the following code. But every time I try to run it, the IDE says that the break is outside the loop
catname = []
print("Enter the name of the cats")
name = input()
if name == '':
break
catname = catname+[name]
print("The cat Names are :")
for catname in name:
print(name)
Can you please help me?
Thanks

You use break when you want to break free from a loop, to exit the loop, to jump to the nearest code after the loop.
Your code doesn't contain a loop, so nothing to break free from, hence the error.

I think you meant exit() instead of break

You use "break" just inside the loop ("for" or "while"), you are trying use brake inside the "if"
How about this:
if name != '':
catname = catname+[name]
print("The cat Names are :")
for catname in name:
print(name)

Your break statement is not in a loop, it's just inside an if statement.
But maybe you want to do something like the following.
If you want to let the user enter an random number of names and print the names out, when the user entered nothing, you can do the following:
# Here we declare the list in which we want to save the names
catnames = []
# start endless loop
while True:
# get the input (choose the line which fits your Python version)
# comment out the other or delete it
name = input("Enter the name of a cat\n") # input is for Python 3
# name = raw_input("Enter the name of a cat\n") # raw_input is for Python 2
# break loop if name is a empty string
if name == '':
break
# append name to the list catnames
catnames.append(name)
print("The cat names are :")
# print the names
for name in catnames:
print(name)

What you are looking for is exit().
However, your code has also other problems, here is a piece of code that does what you probably want (when prompted, enter the names separated by spaces, like: Cat1 Cat2):
name = raw_input("Enter the name of the cats: ")
if len(name) == 0:
exit()
print("\nThe cat Names are:")
for c_name in name.split():
print(c_name)

If this is the entirety of your code, then it's telling you exactly what the problem is:
catname = []
print("Enter the name of the cats")
name = input()
if name == '':
break
You have a break statement in the code that's not contained inside a loop. What do you expect the code above to do?

Related

Python infinite while loop issue

I am trying to make a script that asks for user input in Python, it is supposed to error with the response "Please enter first name", and then return the user back to the initial input question prompt.
This isn't working, instead after asking for both the first and last name if no name is given for both I am thrown into an infinite loop of the first error.
# User input for first name
first_name = input('Enter FIRST name here: ')
# User input for last name
last_name = input('Enter LAST name here: ')
def print_name():
# store user input in separate variable
fname = first_name
lname= last_name
while True:
# throw error if user enters no first name
if len(fname) == 0:
# error msg
print('No FIRST name entered...')
# loop back to prompt asking for first name
continue
else:
# if first name given move on to prompting for last name
# break loop
break
# loop into prompting user for last name
while True:
# throw error if user enters no last name
if len(lname) == 0:
print('No LAST name entered...')
# loop back to prompt asking for last name
continue
else:
# if last name given move on to running print command
# break loop
break
return fname, lname
print(f'your name is {fname} {lname}')
print_name()
Please can someone help me understand whats going wrong here? It should only loop back to asking for a first name (or last name) when nothing is given, other wise it should print the users name to console. both names should be given too, if first name is not given then id expect an error in the first while loop, like wise if last name is not given.
Also is there a better way to do this? using 2 while loops seems wrong?
Don't repeat yourself. If you copy and paste a section of code, stop and think. It should either be a function, or a loop.
def wait_for_input(prompt):
data = ""
while data == "":
data = input(prompt).strip()
return data
def print_name(fname, lname):
print(f'your name is {fname} {lname}')
first_name = wait_for_input('Enter FIRST name: ')
last_name = wait_for_input('Enter LAST name: ')
print_name(first_name, last_name)
Also, don't use comments to repeat what the code says.
The issue is with your infinite loops, you can simplify your function like:
def print_name():
first_name = ""
last_name = ""
# User input for first name
while first_name == "":
first_name = input('Enter FIRST name here: ')
# User input for last name
while last_name == "":
last_name = input('Enter LAST name here: ')
print(f'your name is {first_name} {last_name}')
I have the impression you are new at this:
While-loops generally look as follows:
while <condition>
...
<check_condition>
...
This means that in most cases, at every time the loop is executed, the condition is re-calculated and checked again by the while.
In your case, this would become something like:
while (len(fname) == 0)
<show_error_message>
<get fname again>
The case you have written here (while true) also exists and is used regularly, but in very different cases, like in multi-threaded event-based programs:
while true
<get_event>
This means that a part of the program (a so-called thread) is waiting for an event (like a buttonclick) to be catched and then something happens. This, however, is mostly done in multi-threaded applications, which means that the "main" program is doing something, while a subprogram is handling the events, which are coming in.
I am not fully understanding why you need so many loops. Something like this should do:
def print_name():
fname = input('Enter FIRST name here: ')
if len(fname) == 0:
raise Exception('No FIRST name entered...')
lname= input('Enter LAST name here: ')
if len(lname) == 0:
raise Exception('No LAST name entered...')
print(f"your name is {fname} {lname}")
And if all you wanted is to repeat this loop all you need to do is nest your print_name() function in a loop.
EDIT: Now that I seen other answers, I believe #Tomalak answer is better, was not getting what you really wanted.
Try this code:
def print_name():
# store user input in separate variable
first_name = input('Enter FIRST name here: ')
fname = first_name
while True:
fname = first_name
# throw error if user enters no first name
if len(fname) == 0:
# error msg
print('No FIRST name entered...')
first_name = input('Enter FIRST name here: ')
# loop back to prompt asking for first name
continue
else:
# if first name given move on to prompting for last name
# break loop
break
# loop into prompting user for last name
while True:
last_name = input('Enter LAST name here: ')
lname= last_name
# throw error if user enters no last name
if len(lname) == 0:
print('No LAST name entered...')
# loop back to prompt asking for last name
continue
else:
# if last name given move on to running print command
# break loop
break
return fname, lname
print(f'your name is {fname} {lname}')
print_name()

Error while getting input added into list

I am attempting to create a program that asks for the user to enter his/her name and records the input into a list (Was working towards dictionary but seems like I made a boo boo!) but it is returning with "TypeError: can only concatenate list (not "str") to list". The following is the code.Thanks in advance.
namedic = []
while True:
print ("Please, enter your name:")
name = input()
if len(name) > 3:
print ("Welcome")
else:
print ("Ew, your name have less than 4 letters! Gross! Try a new one")
continue
namedic = namedic + name
print ("Ah, your name have at least 4 words, good name.")
for name in namedic:
print (name)
Your erroring line is namedic = namedic + name. What you're trying to do is add a list (namedic) to a string (name). You should do namedic.append(name) instead.
The + operator isn't used to append elements to a list, as the error shows. You can use the append method for that:
namedic.append(name)
#your code should rather be like this;
namedic = []
while True:
print ("Please, enter your name:")
name = input()
if len(name) > 3:
print ("Welcome")
else:
print ("Ew, your name have less than 4 letters! Gross! Try a new one")
continue
namedic.append(name)
print ("Ah, your name have at least 4 words, good name.")
for name in namedic:
print (name)

Custom python function is not running

names=["aaa","bbb","ccc","ddd","eee"]
itMarks=[90,98,87,98,78]
def printMainMenu():
print(" Main Menu")
print(" =========")
print(" (1)Add Student")
print(" (2)Search Student")
print(" (3)Delete Student")
print(" (4)List Student")
print(" (5)Exit")
choice = int(input("Enter Your choice[1-5]:"))
return choice
def searchStudent(names,itMarks):
name = input("Enter Name")
i = names.index(names)
print("Index is" + i)
def deleteStudent(student,itMarks):
name = input("Enter Name to remove")
student.remove(names)
print("Successfully Deleted" + names)
def removeStudent(names):
name = input("Enter name to remove")
name.remove(name)
print("Successfully deleted" + names)
def addStudent(names, itMarkas):
name = input("Enter Name")
names.append(names)
itMarks = input("Enter IT Marks")
itMarks.append(itMarks)
def listStudent(names, itMarks):
for i in range(0, len(names)):
print(names[1], "", itMarks[i])
names = []
itMarks = []
choice = 1
while choice >= 1 and choice <= 4:
choice = printMainMenu()
if choice == 1:
addStudent(names, itMarks)
elif choice == 2:
searchStudent(names, itMarks)
elif choice == 3:
deleteStudent(names, itMarks)
elif choice == 4:
listStudent(names, itMarks)
elif choice == 5:
print("Exit from the program")
else:
print("invalid choice!")
choice = 1
I am new to the programming in Python. The following Python code is written to do some tasks with the array. There are two array named names and itMarks. And there are some functions :
addStudent() - To add students to the array
searchStudent() - To search a student with in the list.
deleteStudent() - To delete the given student from the list.
listStudent() - To list out the all the names of the students in the list.
When the program runs, it asks to select a choice. Then it do the task according to their choice. But when I run this coding it shows the errors.
Please help me. Thanks in advance.
ERROR :
When I select the choice 1 (Add student) and input name after the error is yield.
Traceback (most recent call last):
File "C:\Users\BAALANPC\Desktop\new 3.py", line 59, in <module>
addStudent(names, itMarks)
File "C:\Users\BAALANPC\Desktop\new 3.py", line 42, in addStudent
name = input("Enter Name")
File "<string>", line 1, in <module>
NameError: name 'rtrt' is not defined
Their so many mistakes in naming
In addStudent
def addStudent(names, itMarkas):
name = input("Enter Name")
names.append(name) # names cant appent it should be name
itMark = input("Enter IT Marks") # here itmark not itMarks
itMarks.append(itMark)
In searchStudent
def searchStudent(names,itMarks):
name = input("Enter Name")
i = names.index(name) # try to find index of name not names
print("Index is" + i)
In deleteStudent
def deleteStudent(student,itMarks):
name = input("Enter Name to remove")
student.remove(name) # try to remove name not names
print("Successfully Deleted" + name)
after change above I run its running you have to also change the naming of the variable for all methods
Output
Main Menu
=========
(1)Add Student
(2)Search Student
(3)Delete Student
(4)List Student
(5)Exit
Enter Your choice[1-5]:1
add student
Enter Name"aaa"
Enter IT Marks111
Main Menu
=========
(1)Add Student
(2)Search Student
(3)Delete Student
(4)List Student
(5)Exit
Enter Your choice[1-5]:
I'm assuming this is the correct form:
def searchStudent(names,itMarks):
name = input("Enter Name")
i = names.index(name)
print("Index is" + i)
note that I changed names to name.
also the same mistake again
def deleteStudent(student,itMarks):
name = input("Enter Name to remove")
student.remove(name)
print("Successfully Deleted" + names)
tl;dr revise your code
searchStudent(): You shouldn't need the itMarks argument if you're not using it inside your function at all. names refers to the list of names, but you are really trying to search name. i is an integer that is attempting to be concatenated with a string. Not allowed. It should be str(i).
deleteStudent(): Better to keep your arguments consistent and use names rather than student. Again, same problem as above, should be .remove(name) and you shouldn't need the itMarks argument. print statement should refer to name not names.
removeStudent(): This is the same code as deleteStudent(), but not used, so not sure why it's there.
addStudent(): Typo in the argument, .append(name). You have a global variable and a local variable named the same thing, which are conflicting to the program. Change the input set to itMark and .append(itMark).
listStudent(): print statement has a typo, 1 should be i. Not sure why the empty string is included as well.
Underneath your function def's, you restate your variables as empty lists. This can lead to ValueErrors from a lot of your functions as you're trying to look something up or modify something in an empty list. Simply delete this code.
Additionally, any error will break your while loop. I suggest adding more booleans or using a try except clause to catch these errors.
Good luck!

How to write to a text file using iteration?

My code does not write to a file, what am I doing wrong? I am trying to program to continue to ask for products until the user does not enter a product code. I want all products to be saved in the file.
store_file = open("Database.txt", "w")
NewProduct = ""
while NewProduct != False:
contine = input("Press 1 to enter a new product press 2 to leave: ")
if contine == "1":
print("Enter your product information")
information = []
product = input("What's the product code: ")
information.append(product)
description = input("Give a description of the product: ")
information.append(description)
price = input("Enter price of product: ")
information.append(price)
information = str(information)
clean = information.replace("]","").replace("[","").replace(",","").replace("'","")
store_file.write(clean)
elif contine == "2":
NewProduct = False
else:
print("Your input is invalid")
store_file.close
I got the program working with the following adjustments. See comments for explanations:
store_file = open("Database.txt", "w")
NewProduct = ""
while NewProduct != False:
continue = raw_input("Press 1 to enter a new product press 2 to leave: ")
#Changed to raw_input because input was reading in an integer for 1 rather than a
#string like you have set up. This could be specific to my IDE
if continue == "1":
print("Enter your product information")
information = []
product = raw_input("What's the product code: ")
information.append(product)
description = raw_input("Give a description of the product: ")
information.append(description)
price = raw_input("Enter price of product: ")
information.append(price)
information = str(information)
clean = information.replace("]","").replace("[","").replace(",","").replace("'","")
store_file.write(clean + "\n")
#Added a line break at the end of each file write
elif contine == "2":
NewProduct = False
else:
print("Your input is invalid")
store_file.close() #Added parentheses to call the close function
I'm assuming the problem here is that you're using Python 2, and input isn't doing what you think it does. In Python 2, input evals the input as if it were Python source code, so if someone enters 2, it's going to return the int value 2, not "2". In Python 2, you want to use raw_input, always (eval-ing random user input not being secure/reliable).
Also, while on CPython (the reference interpreter) files tend to naturally close themselves when they go out of scope, you made an effort to close, but forgot to actually call the close method; store_file.close looks up the method without calling it, store_file.close() would actually close it. Of course, explicit close is usually the wrong approach; you should use a with statement to avoid the possibility of forgetting to close (or of an exception skipping the close). You can replace:
store_file = open("Database.txt", "w")
...
store_file.close()
with:
with open("Database.txt", "w") as store_file:
... do all your work that writes to the file indented within the with block ...
... When you dedent from the with block, the file is guaranteed to be closed ...
There are other issues though. What you're doing with:
information = str(information)
information = information.replace("]","").replace("[","").replace(",","").replace("'","")
is terrible. I'm 99% sure what you really wanted was to just join the inputs with spaces. If you switch all your input calls to raw_input (only on Python 2, on Python 3, input is like raw_input on Python 2), then your list is a list of str, and you can just join them together instead of trying to stringify the list itself, then remove all the list-y bits. You can replace both lines above with just:
information = ' '.join(information)

Having trouble parsing a txt file into a list full of zip codes in my zipcode lookup program

Hello everyone thanks for looking into my problem. What I am trying to do is write a "Structured" program in python that takes txt from a file and parses it into lists. Then after closing the file, I need to reference the user input (zipcode) in those lists and then print out the city and state according to the zipcode that they entered. My instructor is having us use structure by making several functions. I know there are probably lots of more efficient ways of doing this, but I must keep the structure thats in place.
EDIT
Here is my code(Current):
#-----------------------------------------------------------------------
# VARIABLE DEFINITIONS
eof = False
zipRecord = ""
zipFile = ""
zipCode = []
city = []
state = []
parsedList = []
#-----------------------------------------------------------------------
# CONSTANT DEFINITIONS
USERPROMPT = "\nEnter a zip code to find (Press Enter key alone to stop): "
#-----------------------------------------------------------------------
# FUNCTION DEFINITIONS
def startUp():
global zipFile
print "zipcode lookup program".upper()
zipFile = open("zipcodes.txt","r")
loadList()
def loadList():
while readRecord():
pass
processRecords()
def readRecord():
global eof, zipList, zipCode, city, state, parsedList
zipRecord = zipFile.readline()
if zipRecord == "":
eof = True
else:
parsedList = zipRecord.split(",")
zipCode.append(parsedList[0])
city.append(parsedList[1])
state.append(parsedList[2])
eof = False
return not eof
def processRecords():
userInput = raw_input(USERPROMPT)
if userInput:
print userInput
print zipCode
if userInput in zipCode:
index_ = zipcode.index(userInput)
print "The city is %s and the state is %s " % \
(city[index_], state[index_])
else:
print "\nThe zip code does not exist."
else:
print "Please enter a data"
def closeUp():
zipFile.close()
#-----------------------------------------------------------------------
# PROGRAM'S MAIN LOGIC
startUp()
closeUp()
raw_input("\nRun complete. Press the Enter key to exit.")
Here is a sample from the zipcode txt file:
00501,HOLTSVILLE,NY
I am definitely stuck at this point and would appreciate your help in this matter.
EDIT
Thanks for all the help everyone. I really do appreciate it. :)
why you fill the lists zipcode, city , state like that, i mean in each user entry we get the next line from the file
i think that you should do :
def loadList():
# Fill all the list first , make the readRecord() return eof (True or False).
while readRecord():
pass
# than process data (check for zip code) this will run it only one time
# but you can put it in a loop to repeat the action.
processRecords()
about your problem :
def processRecords():
userInput = raw_input(USERPROMPT)
# Check if a user has entered a text or not
if userInput:
# check the index from zipcode
if userInput in zipcode:
# the index of the zipcode in the zipcode list is the same
# to get related cities and states.
index_ = zipcode.index(userInput)
print "The city is %s and the state is %s " % \
(city[index_], state[index_])
else:
print "\nThe zip code does not exist."
else:
print "Please enter a data"
one of the beauties of Python is that it's interactive. if you take processRecords() out of loadList(), and then at the bottom of your program put:
if __name__ == '__main__':
processRecords()
Then, from the command prompt, type "python". You'll get the Python shell prompt, ">>>". There you type:
from zipcodes import * # this assumes your program is zipcodes.py
dir() # shows you what's defined
print zipCode # shows you what's in zipCode
that ought to help debugging.
Strings don't have an append method like lists do. What I think you're trying to do is append the strings zipCode, city, and state to parsedList. This is the code you'd use to do that:
parsedList.append(zipCode)
parsedList.append(city)
parsedList.append(state)
Or, even more compactly:
parsedList = [zipCode, city, state]
Let me know if you get another error message and I can offer more suggestions.

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