Return value if string has x character - python

The program asked is:
"besides testing if the length of the given string is more than ten characters, it also tests if there is the character "X" (capital X) in the given string. If the string is longer than 10 characters and it has X in it, the tester subfunction returns a value True to the main function, otherwise False.
If the subfunction returns True to the main function, the program prints "X spotted!". As earlier, if the user inputs "quit", the program terminates."
This is what I tried, but the part of checking the x character does not work at all
def check(st,res="Too short"):
if len(st)>=10:
if checkX(st):
st=st+"\nX spotted!"
return st
else:
return res
def checkX(st):
for i in st:
if i=="X":
return True
return False
def main():
while True:
st=input("Write something (quit ends): ")
if st=="quit":
break
print(check(st))
It only checks if introduced string length is equal or higher than 10 characters.

The code works.
What should you change in your code:
You can use the in operator:
if "blah" not in somestring:
continue
Does Python have a string 'contains' substring method?
Do a real "main":
if __name__ == '__main__':
What you can do if you want to keep the main() function:
A module can discover whether or not it is running in the main scope by checking its own name, which allows a common idiom for conditionally executing code in a module when it is run as a script or with python -m but not when it is imported:
if __name__ == "__main__":
# execute only if run as a script
main()
main — Top-level script environment
Result (this code works, it is simplier, more pythonic and respect pep8):
def check_input(tested_sentence: str, result: str = "Too short"):
if len(tested_sentence) >= 10:
if "X" in tested_sentence:
result = tested_sentence + "\nX spotted!"
else:
result = tested_sentence
return result
def main():
while True:
sentence = input("Write something (quit ends): ")
if sentence == "quit":
break
print(check_input(sentence))
if __name__ == '__main__':
main()
Code Style — The Hitchhiker's Guide to Python

Related

python testing, how handle 'continue' statement loop

I'm learning how to use Python. I have a function with a conditional inside of it, if an invalid input is provided, it should restart the loop until a valid input is provided.
Unfortunately, this "restarting" behavior is causing an infinite loop within my tests (it circularly provides the wrong input). How can I pause, or break, or limit the output to one instance so I can test the returned string?
function:
def confirm_user_choice(choice: str):
while True:
user_response = input(f"\nYou chose '{choice}', is this correct? y/n ")
if user_response == "y":
return True
elif user_response == "n":
return False
else:
print("\nSelect either 'y' (yes) or 'n' (no)")
test:
import unittest
from unittest import mock
from src.utils.utils import addValues, confirm_user_choice
class TestConfirmUserChoice(unittest.TestCase):
def test_yes(self):
with mock.patch("builtins.input", return_value="y"):
result = confirm_user_choice("y")
self.assertEqual(result, True)
def test_no(self):
with mock.patch("builtins.input", return_value="n"):
result = confirm_user_choice("n")
self.assertEqual(result, False)
def test_invalid_input(self):
with mock.patch("builtins.input", return_value="apple"): <-- triggers func else case
result = confirm_user_choice("apple")
self.assertEqual(result, False)
You have a partial function: on a proper input, it will return a Boolean value, but it may not return at all, and you can't test that an infinite loop is indeed infinite.
To make it more testable, allow the function to take an optional iterable value that defaults to sys.stdin, allowing you to control what the function reads (and how long it will attempt to do so.)
def confirm_user_choice(choice: str, responses: Optional[Iterable[str]] = None):
if responses is None:
# An infinite stream of calls to input()
responses = iter(lambda: input(f"\nYou chose '{choice}', is this correct? y/n "), None)
for user_response in responses:
if user_response == "y":
return True
elif user_response == "n":
return False
else:
print("\nSelect either 'y' (yes) or 'n' (no)")
else:
# Note: cannot be raised from the default value of responses
raise ValueError("Unexpected end of responses")
Now your test can simply pass canned lists of responses, and either catch the expected ValueError, or look at the returned Boolean value.
import unittest
from src.utils.utils import addValues, confirm_user_choice
class TestConfirmUserChoice(unittest.TestCase):
def test_yes(self):
result = confirm_user_choice("y", ["y"])
self.assertTrue(result)
def test_eventual_yes(self):
result = confirm_user_choice("y", ["apple", "pear", "y"])
self.assertTrue(result)
def test_no(self):
result = confirm_user_choice("y", ["n"])
self.assertFalse(result)
def test_no_valid_input(self):
with self.assertRaises(ValueError):
result = confirm_user_choice(["apple"])
continue does nothing in your code
continue alows you to ignore a part of the code for some instance of the loop.
For example :
for i in range(2):
if i < 1:
continue
print(i)
Output :
1
For what you want to do, don't forget while is suppose to end when a condition is meet. Hence bypassing the condition using while True: and then using a if to exit your loop is a bit counter productive.
Just use the while condition :
user_response = ""
while user_response not in ["y", "n"]:
user_response = input("y/n ? ")
print(user_response)
Happy programming
I'm new to Python myself but in my understanding, unit tests investigate how function handle different inputs based on the function's return value or exceptions raised (if any).
Your function only exits when the user inputs either "y" or "n" or when an error is raised (for instance, if the user provides Crtl-Z). Your while loop does not break when a user inputs 'apple.' There is no return value for pytest (or the like) to inspect.
If you really want to test this, you'd have to rewrite your function so that's a little more modular. It would have to feature at least three different return values, including one that implies that the input was invalid.

Python: How to determine if a String can be converted to an integer with no issues

I am writing a program that has multiple functions to execute, and the user selects which one runs by inputting a number. I also want the user to be able to let the user cancel the request by typing "cancel".
Right now this is my code:
func = input("Requested Operation: ")
if func == 'Cancel' or func == 'cancel':
break
elif func == '' or func == ' ' or func == '0':
func = 0
elif type(int(func)) is int:
func = int(func)
else:
fail = True
Context: Function 0 displays a list of the available items to choose from, so I want whitespace or 0 to work as displaying the project list. If the user types "Cancel" or "cancel" it will end the program.
The problem I am having is line 6 (the 2nd elif). My goal is to set the fail variable to True if the user inputs a string that isn't a cancel command, so the code breaks right there and starts over. The problem is, how do I preemptively check if a string can be converted to an integer in the first place? My current iteration returns the error invalid literal for int() with base 10: 'asdg' (asdg being the random nonsense that should make fail = True).
Also, I understand this method is probably super inefficient. Essentially, I want the conditional to be "if func is cancel, break. If func is whitespace or '0', then it equals 0. If func is some non-0 integer, convert the string to an integer and continue. Otherwise, set fail to True and break."
My knowledge of python is minimal so I would very much appreciate a full explanation or link to documentation so I can learn as much as possible.
Thanks in advance :)
Edit: This is the entire module
import projects.dice_app as dice_app
import projects.text_to_math as text_to_math
def main():
f = open("readme_files/index.txt")
p = open("readme_files/projects.txt")
print(f.read())
func = 0
while True:
fail = False
func = input("Requested Operation: ")
if func == 'Cancel' or func == 'cancel':
break
elif func == '' or func == ' ' or func == '0':
func = 0
elif type(int(func)) is int:
func = int(func)
else:
fail = True
break
if func == 0:
p = open("readme_files/projects.txt")
print(p.read())
elif func == 1:
dice_app.dice_func()
elif func == 2:
text_to_math.ttm_func()
else:
print("Invalid operation. Please try again.")
if __name__ == "__main__":
fail = False
main()
while fail == True:
main()
elif func.isnumeric():
func = int(func)
try :
func = int(func)
except ValueError:
print('not a number')
This should work

python calling definition by variable name

a python beginner here. My previous programming experience is with basic in the eighties, and logic programming in a proprietary system, neither of which is much help for learning python. So, to my question:
I'm writing a math quiz program (just for learning), and I've made a "main menu" by defining a function block; within it, if input is a then another func addition() is called, if input is s then func subtraction() is called and this works as intended. Within those function blocks, I'm setting a global variable quiztype to name of that function. Then I call yet another function again() from within those, to query if user wants another question of the same sort, if yes, I try to return to the relevant function with quiztype () and this fails with TypeError: 'str' object is not callable.
I did find some seemingly-related topics but either couldn't implement the answers or didn't even understand what they were talking about as I'm a beginner.
What options do I have for returning to the previously executed function?
Here's the code: (notice that variable names are not what above - different language)
from random import randint
def Alku ():
kysy = True
while kysy:
lasku = input('Yhteen, Vähennys, Lopeta? ')
if lasku == 'y':
Yhteenlasku ()
kysy = False
elif lasku == 'l':
break
kysy = False
def Uudestaan ():
kysy = True
while kysy:
samauudestaan = input('uudestaan? (k/e)? ')
if samauudestaan == 'k':
Lasku()
kysy = False
elif samauudestaan == 'e':
Alku ()
kysy = False
def Yhteenlasku ():
global Lasku
Lasku='Yhteenlasku'
n1=(randint(1,10))
n2=(randint(1,10))
a1=n1+n2
print(n1, end="")
print(" + ", end="")
print (n2, end="")
print(" = ", end="")
a2=int(input())
print()
if a1==a2:
print('oikein!')
elif a1!=a2:
print('väärin!')
Uudestaan()
Alku ()
And what is returned in terminal:
Traceback (most recent call last):
File "laskut2.py", line 43, in <module>
Alku ()
File "laskut2.py", line 8, in Alku
Yhteenlasku ()
File "laskut2.py", line 41, in Yhteenlasku
Uudestaan()
File "laskut2.py", line 19, in Uudestaan
Lasku()
TypeError: 'str' object is not callable
Your code is fine as it stands, although your global declaration is in an odd place. Still, remove the inverted comma's around your definition of Lasku which is defining it as a string and it will work.
global Lasku
Lasku=Yhteenlasku
P.S. Welcome back to programming!
In response to your question, globals would normally be declared at the beginning of your code or when the data to define becomes available but in this case you are defining it as a function, so you can't define it until the function has been defined. I guess as long as it works, where it is is fine. Personally, in this case, I'd define it here:
global Lasku
Lasku=Yhteenlasku
Alku ()
We really need to see your code to see what you want to achieve but from the sound of it you want to do something like this. From the question it look like you will be recalling function within functions and returning functions, creating recursions which is not that pythonic and also will eventually throw errors and the other is not really needed in this situation. jedruniu has put really quite a good explanation on function variable assignment too.
Less robust version:
def addition():
pass # Put code here
def subtraction():
pass # Put code here
def menu():
while True:
cmd = input("Addition or subtraction? (a/s): ")
if cmd == "a":
addition()
elif cmd == "s":
subtraction()
menu()
Other version (w/ score):
def addition():
# Put code here
result = True
return result # Will be added to score, so any integer or True/False
def subtraction():
# Put code here
result = True
return result # Will be added to score, so any integer or True/False
def menu():
score = 0
while True:
cmd = input("Addition or subtraction? (a/s/exit): ").strip().lower()
if cmd == "exit":
break
elif cmd == "a":
score += addition()
elif cmd == "s":
score += subtraction()
else:
print("Unknown option...")
# Do something with score or return score
if __main__ == "__main__":
menu()
You can assign function to a variable (because function is in Python first-class citizen), so effectively, for example:
def fun1():
print("fun1")
def fun2():
print("fun2")
def fun3():
print("fun3")
f1 = fun1
f2 = fun2
f3 = fun3
functions = {
"invoke_f1" : f1,
"invoke_f2" : f2,
"invoke_f3" : f3
}
functions["invoke_f1"]()
function_to_invoke = functions["invoke_f2"]
function_to_invoke()
yields:
fun1
fun2
More reading: https://en.wikipedia.org/wiki/First-class_function
In your specific example, modify your Uudestaan function.
def Uudestaan ():
Lasku = Yhteenlasku #Add this line
kysy = True
while kysy:
samauudestaan = input('uudestaan? (k/e)? ')
if samauudestaan == 'k':
Lasku()
kysy = False
elif samauudestaan == 'e':
Alku ()
kysy = False
because you were trying to invoke string, and this is not possible. Try to invoke type(Lasku) in your case and you'll see that it is of type str. Invoke it in function with my modification and you'll see type of function.
However I am not sure what is going on in this code, is this finnish? swedish?

Why dont my functions work?

This is python 3, this code basically checks if a word is the same when read backwards. When i execute this through Visual Studio, nothing happens, and I get the prompt to press any key to continue...
if "__name__" == "__main__":
StartProgram()
def StartProgram():
Input = AskForDataSimple()
print(CheckIfPalindrome(Input))
def AskForDataSimple():
print("Please input the line to test.")
In = input()
return In
def CheckIfPalindrome(x):
if x[::-1] == x:
return True
else:
return False
Please note that this simpler version actually works:
x = input()
if x[::-1] == x:
print(True)
else:
print(False)
if "__name__" == "__main__":
Change this to
if __name__ == "__main__":
__name__ is a variable containing name of this module. You need these line so that your main logic would be used only if this file is executed directly, not when imported as a module by another code.
Still it won't work, because you need to define the function you call before these lines: move these lines to the end of the file.
Also, this
def CheckIfPalindrome(x):
if x[::-1] == x:
return True
else:
return False
can be replaced with
def CheckIfPalindrome(x):
return x[::-1] == x
Move main function to bottom of file and try it
if __name__ == "__main__":
StartProgram()

Python- how to init random function

I am a beginer python learner. I am trying to create a basic dictionary where random meaning of words will come and user have to input the correct word. I used the following method, but random doesn't work. I always get the first word first and when the last word finishes, I get infinite 'none' until I kill it. Using python 3.2
from random import choice
print("Welcome , let's get started")
input()
def word():
print('Humiliate')
a = input(':')
while a == 'abasement':
break
else:
word()
# --------------------------------------------------------- #
def word1():
print('Swelling')
a = input(':')
while a == 'billowing':
break
else:
word()
# ------------------------------------------------------------ #
wooo = [word(),word1()]
while 1==1:
print(choice(wooo))
is there any faster way of doing this and get real random? I tried classes but it seems harder than this. Also, is there any way I can make python not care about weather the input is capital letter or not?
To answer one part of your question ("is there any way I can make python not care about weather the input is capital letter or not?"): use some_string.lower():
>>> "foo".lower() == "foo"
True
>>> "FOO".lower() == "foo"
True
An this is to help you how you could improve the structure of your code:
import sys
from random import choice
WORDPAIRS = [('Humiliate', 'abasement'), ('Swelling', 'billowing')]
def ask():
pair = choice(WORDPAIRS)
while True:
answer = raw_input("%s: " % pair[0]).lower()
if answer == pair[1]:
print "well done!"
return
def main():
try:
while True:
ask()
except KeyboardInterrupt:
sys.exit(0)
if __name__ == "__main__":
main()
It works like that:
$ python lulu.py
Swelling: lol
Swelling: rofl
Swelling: billowing
well done!
Humiliate: rofl
Humiliate: Abasement
well done!
Swelling: BILLOWING
well done!
Humiliate: ^C
$
wooo = [word, word1]
while 1:
print(choice(wooo)())
But in any case it will print you None, cause both of your functions return nothing (None).

Categories