So I am making a quick calculator script in Python, and I need to take apart a short string. The program first displays a short welcome message, then a prompt asks What they want to do calculate, and shows them the correct format. The functionality is there to do the calculation but unfortunately, I can not get the string dissecting bit working.
Here's my code
print ("--------------------------------------")
print (" ")
print ("Advanced Quick Calculator")
print ("By Max M, licenced under GPLv3")
print (" ")
print ("--------------------------------------")
statement = raw_input ("Please enter your mathematical statement [3 3 plus minus times divide]: ")
strnum1 = statement[:1]
print ("strnum1 : " + strnum1)
#num1 = int (strnum1)
strnum2 = statement[:4]
print ("strnum2 : " + strnum2)
#num2 = int (strnum2)
operation = statement[5:11]
print ("operation : " + operation)
#if operation == "+":
# ans = num1 + num2
#if operation == "-":
# ans = num1 - num2
#if operation == "*":
# ans = num1 * num2
#if operation == "/":
# ans = num1 / num2
#print ("The answer is : "), ans
This looks like a job for regular expressions:
>>> import re
>>> match = re.search(r'(\d+)\s*([+*/-])\s*(\d+)', '42 + 7')
>>> match.group(1) # <-- num1
'42'
>>> match.group(2) # <-- operation
'+'
>>> match.group(3) # <-- num2
'7'
Slicing the input like you're currently doing is probably not a good idea as it greatly restricts the allowed formats. For instance, what if the user accidentally precedes his input with a couple of spaces? Regular expressions can handle such cases well.
I'm not going to do your homework for you, but I will point you to the answer to your question (hint: it looks like you're trying to split on spaces instead of comma's like in the link, so adjust the code accordingly).
How to read formatted input in python?
Related
Write a python program to display the outputs of following arithmetic operations on two numbers,which is accepted from user side ? a)Addition b)Subtraction c)Multiplication d)Division//
i wrote this code but it is not working
a = int(input("Enter First Number: "))
b = int(input("Enter Second Number: "))
print("Enter which operation would you like to perform?")
ko= input("Enter any of these char for specific operation +,-,*,/: ")
result = 0
if ko == '+':
result = a + b
elif ko == '-':
result = a - b
elif ko == '*':
result = a * b
elif ko == '/':
result = a / b
else:
print("Error")
print(num1, ko , num2, ":", result)
can anybody please tell me what i did wrong or post the correct code
Firstly, the first line of your program isn't indented properly - You need to remove the indentation before the first line.
Here's a guide to proper indentation in python: https://docs.python.org/2.0/ref/indentation.html
Secondly, the variables that you call in the final print function do not exist. "num1" and "num2" aren't defined - you need to use "a" and "b", because that's what you name the return values of the input functions you call in the beginning of the program. So you can either change "num1" and "num2" to "a" and "b", or vice versa.
The final code would look something like this:
a = int(input("Enter First Number: "))
b = int(input("Enter Second Number: "))
print("Enter which operation would you like to perform?")
ko = input("Enter any of these char for specific operation +,-,*,/: ")
result = 0
if ko == '+':
result = a + b
elif ko == '-':
result = a - b
elif ko == '*':
result = a * b
elif ko == '/':
result = a / b
else:
print("Error")
print(a, ko, b, ":", result)
Also, while programming in any language, it's advised to use descriptive names for variables - It might take some extra typing, but it will save a lot of hassle in bigger and more complex programs, and also it's a good practice.
Finally, this program (even though it gets the job done), isn't the most efficient or beginner-friendly solution for a calculator program. Here are some resources to help you understand it:
"Building a Basic Calculator | Python ": https://www.youtube.com/watch?v=HBbrSDGGOkw
or, if you prefer reading:
https://www.digitalocean.com/community/tutorials/how-to-make-a-calculator-program-in-python-3
I'd also like to tell you that reading the error messages you get in the console would've helped you understand the problem better, and maybe even come up with a solution, but we're here to help you :)
The error was in your last print statement...num1 and num2 should replace as a and b.
So the last line should be:
print(a, ko , b, ":", result)
This question already has answers here:
Asking the user for input until they give a valid response
(22 answers)
Closed 2 years ago.
I'm very new to python, just started learning, and wanted to test my skills by building a simple arithmetic calculator. I've tied up most loose ends in my code, but don't know how to provide an error message and new input line to the user when they place a letter/word in the input line for numbers. Again, I'm very new to python and have no idea how to fix this. Also curious about how ugly my code looks. Any advice is appreciated, thanks.
print("Welcome to the Basic Python Calculator!")
def calculator():
num1 = input("Name your first number: ")
num2 = input("Name your second number: ")
operator = input("Name an operation. Add, Subtract, Multiply, or Divide. (Match Capitalization)\n")
while operator != "Add" and operator != "Subtract" and operator != "Multiply" and operator != "Divide":
operator = input("Name an operation. Add, Subtract, Multiply, or Divide. (Match Capitalization)\n")
if operator == "Add":
result = float(num1) + float(num2)
print(num1 + " + " + num2 + " = " + str(result))
elif operator == "Subtract":
result = float(num1) - float(num2)
print(num1 + " - " + num2 + " = " + str(result))
elif operator == "Multiply":
result = float(num1) * float(num2)
print(num1 + " ● " + num2 + " = " + str(result))
elif operator == "Divide":
result = float(num1) / float(num2)
print(num1 + "/" + num2 + " = " + str(result))
calculator()
You can do this by using a try/catch block along with a while loop. So when you want to take number input, do this
while true:
user_input = input("Enter a number")
try:
user_input_number = int(user_input)
break
except:
print("ERROR")
print(user_input_number)
You can simply use isnumeric() (i.e num1.isnumeric(), num2.isnumeric()) to see if you have a number or not. and using that you'll know how to deal with the input. You won't need a try catch, although having one would be a good idea.
Side note for floats: for float strings, one quick way could be to remove . and check the resulting string with isnumeric to know if you are dealing with numbers
Recently I created a 24 game solver with python
Read this website if you do not know what the 24 game is:
https://www.pagat.com/adders/24.html
Here is the code:
from itertools import permutations, product, chain, zip_longest
from fractions import Fraction as F
solutions = []
def ask4():
num1 = input("Enter First Number: ")
num2 = input("Enter Second Number: ")
num3 = input("Enter Third Number: ")
num4 = input("Enter Fourth Number: ")
digits = [num1, num2, num3, num4]
return list(digits)
def solve(digits, solutions):
digit_length = len(digits)
expr_length = 2 * digit_length - 1
digit_perm = sorted(set(permutations(digits)))
op_comb = list(product('+-*/', repeat=digit_length-1))
brackets = ([()] + [(x,y)
for x in range(0, expr_length, 2)
for y in range(x+4, expr_length+2, 2)
if (x,y) != (0,expr_length+1)]
+ [(0, 3+1, 4+2, 7+3)])
for d in digit_perm:
for ops in op_comb:
if '/' in ops:
d2 = [('F(%s)' % i) for i in d]
else:
d2 = d
ex = list(chain.from_iterable(zip_longest(d2, ops, fillvalue='')))
for b in brackets:
exp = ex[::]
for insert_point, bracket in zip(b, '()'*(len(b)//2)):
exp.insert(insert_point, bracket)
txt = ''.join(exp)
try:
num = eval(txt)
except ZeroDivisionError:
continue
if num == 24:
if '/' in ops:
exp = [(term if not term.startswith('F(') else term[2])
for term in exp]
ans = ' '.join(exp).rstrip()
print("Solution found:", ans)
solutions.extend(ans)
return ans
print("No solution found for:", ' '.join(digits))
def main():
digits = ask4()
solve(digits, solutions)
print(len(solutions))
print("Bye")
main()
Right now, my code only shows one solution for the numbers given, even when there are clearly more solutions.
So if someone knows how to do this please help me
Thanks
You're not allowing the code to finish it's task before all of the solutions have been calculated and listed. Better to save the solutions in a list/array instead of returning it straight away.
Your function is returning as soon as it finds a solution. Delete the return statement. After the loop, you can return the list of all solutions if desired. To check if there were none, see if the length of the list is zero (so you know when to say there are no solutions).
I would also suggest making solutions local to solve, instead of global.
thanks for taking time to read this.
I have to create a program that generates 10 random maths questions based around =, - and *. I have the program working but everytime I run it after the main program it prints "none" even though that's not in my program.Any help at all would be much appreciated. Thank you.
import random
print ("Welcome")
name=input("What's your name?")
print("Nice to meet you", name, ",you will be given 10 multiplication, addition and subtraction questions.")
Num1 = random.randint(1,12)
Num2 = random.randint(1,12)
sign = random.randint(1,3)
if sign == 1: # If the random number generated is 1
question = Num1 + Num2
rightanswer1 = Num1 + Num2
answer1=input(print("What is", question ,"?"))
if answer1 == rightanswer1:
print("Well Done!")
if answer1 != rightanswer1:
print("Sorry, that's incorrect, the answer was", rightanswer1)
if sign == 2:
question = Num1 - Num2
rightanswer2 = Num1 - Num2
answer2=input(print("What is", Num1, "-", Num2 ,"?"))
if answer2 == rightanswer2:
print("Well done!")
elif answer2 != rightanswer2:
print("Sorry, that's incorrect, the answer was", rightanswer2)
if sign == 3:
question = Num1 * Num2
rightanswer3 = Num1 * Num2
answer3=input(print("What is", Num1, "x", Num2 ,"?"))
if answer3 == rightanswer3:
print("Well done!")
elif answer3 != rightanswer3:
print("Sorry, that's incorrect, the answer was", rightanswer3)`
> Welcome
> What's your name? John
> Nice to meet you John ,you will be given 10 multiplication, addition and subtraction questions.
> What is 12 x 3 ?
> None 36
> Sorry, that's incorrect, the answer was 36
I think you are using python 3. In python 3 input is like raw_input in python 2. So you get the string as input. So convert it into int
var = int(input("Enter a number: "))
So in your code make it as
print("What is", Num1, "x", Num2 ,"?")
answer3 = input()
answer3 = int(answer3)
See this:
whats-the-difference-between-raw-input-and-input-in-python3-x
I'm reluctant to just give you an answer that just does it for you, so instead i'll provide you with a few hints to improve things. (i.e. this isn't an answer, just too large of a comment - and more like a codereview answer)
First off, you use a structure like this:
if x == 1:
#do something
if x == 2:
#do something else
...
In this case, which it makes no difference, it is easier to read if you use the if syntax as intended:
if <condition>:
#do this if the above test is true.
elif <more conditions>:
#do this only if the first test is false and this one is true
elif <more conditions>:
#same as above, except for the second test must be false too
else:
#do this if all the above tests are false
So you could use this something like:
if sign == 1:
...
elif sign == 2:
...
elif sign == 3:
...
else:
# something weird happened...
Which would make that section of the program easier to follow.
The same thing can be done with the if answer1 == rightanswer1: sections;
if answer1 == rightanswer1:
#correct!
else:
#incorrect.
That would be a clearer was to do it. You seem to have used the if...elif style in a couple of them, but not the first one.
Once you have this, it will be a little clearer.
The next way you could improve things is by removing duplicated code. You don't need separate branches for each sign, you can just roll it all into one:
number1 = randint(1,12)
number2 = randint(1,12)
op = randint(1,3)
question_string = "%d %s %d = ?" % (number1, number2, ["+", "-", "*"][op])
result = None
if op == 1:
result = number1 + number2
elif op == 2:
result = number1 - number2
elif op == 3:
result = number1 * number2
This will do most of the logic for you, and generate the strings you want, without duplicating all of the other code.
Small changes like this can make things much more readable.
It's printing None because the print() function returns None and you're passing that value of None from print() as the prompt to your input() functions. Eg,
answer3=input(print("What is", Num1, "x", Num2 ,"?"))
So print("What is", Num1, "x", Num2 ,"?") prints its stuff, and returns None, which then gets printed as the prompt by input().
A simple way to fix this is to just move your print() function calls out of your input() functions.
Eg,
print("What is", Num1, "x", Num2 ,"?")
answer3=input()
However, there's another major problem with your program: the rightanswer variables are ints, but the inputted answers are strings. To compare them properly they need to be the same type. So you should either convert the inputted answers to int, or alternatively, convert the rightanswers to str.
There are two problems with how you use the input function:
You misuse the prompt argument
You forget to convert the result
First, have a better look at the reference of the input function
The prompt argument
input takes a string as argument that will be displayed ("prompted") to the user to indicate that the program is waiting an input. The print function also displays a string to the user, but it doesn't return anything. It does its job and that's all (and in Python a function that returns nothing, returns None). That's what input gets to display, so it displays None. You should use format instead. It will format and return the formatted string that input can display:
answer1_as_str=input("What is {} ?".format(question))))
or
answer2_as_str=input("What is {:d} - {:d} ?".format(Num1, Num2)))
The return value
input returns the user input as a string contrary to python 2 (i.e. exactly as entered). So you have to convert the input to the desired type if you need it. If you type 10 for example, the input will return "10". If you need an int, you have to convert it yourself.
answer1 = int(answer1_as_str)
It looks like you don't really understand how input() works. You might also want to review the different datatypes and conditional statements. Other than that, it was a very good attempt. Here's my solution:
from random import randint
print("Welcome")
name = input("What's your name?\n")
print("Nice to meet you " + name + ", you will be given 10 multiplication, addition and subtraction questions.")
for i in range(10):
print("\nProblem " + str(i+1))
num1 = randint(1,12)
num2 = randint(1,12)
sign = randint(1,3)
if sign == 1:
question = str(num1) + " + " + str(num2)
answer = num1 + num2
elif sign == 2:
question = str(num1) + " - " + str(num2)
answer = num1 - num2
else:
question = str(num1) + " x " + str(num2)
answer = num1 * num2
user_answer = input("What is " + question + "? ")
if user_answer == str(answer):
print("Well done!")
else:
print("Sorry, that's incorrect, the answer was", answer)
I am very much interested in Python and I decided to learn it.
I covered many things but I am stuck when try to make a Calculator in which we just need to type the numbers and the operation type
For Example- 10 ^ 2
The thing that happens is I get no answer. And i use Command Prompt
for the output.
My Code looks like this:
# Calculator
print " "
print " Calculator "
print " "
num = int(raw_input(">> ")).split()
num1 = int(num[0])
op = num[1]
num2 = int(num[2])
if (op=='+'):
print ">>>", num1 + num2
elif (op=='-'):
print ">>>", num1 - num2
elif (op=='*'):
print ">>>", num1 * num2
elif (op=='/'):
print ">>>", num1 / num2
elif (op=='^'):
print ">>>", pow(num1,num2)
elif (op=='%'):
print ">>>", num1 % num2
I use Python 2.7.
Please Help Me For The Same.
You have to remove the int cast, that is
num = raw_input(">> ").split() # remove the int cast
Output will then be:
>> 10 ^ 2
>>> 100
Change
num = int(raw_input(">> ")).split()
To
num = raw_input(">> ").split()
If you enter 2 ^ 10, for example, num will now be the array ['2', '^', '10'] and the rest of your code will work.
If you do int() on your raw_input it will not work since you are trying to convert a string like "2 ^ 10" to an int.
num = int(raw_input(">> ")).split()
should be changed to
num = (raw_input(">> ")).split()
you cannot split a number at least for what I know