Programming Forums > Script Programming > Python

Nebula · Jan 17th, 2006, 11:20 PM

I really just winged this one, no tutorial help, no nothing. Just took my knowldge and tried something. Chances are, its completly wrong. I had some trouble running it and i thought it might be just some mundane error but if it is more than just a typo of incorrect statement, I would like to know what it is. Thnx a million.

Its a, not-completed, calculator program ---->

(Toggle Plain Text)

operator = raw_input ("Please enter the prefered operator: +, -, *, /")

if operator == '+' then:
	print "Addition it is!
	number_1 = input ("Please insert a number below 1,000,000:")
	number_2 = input ("Please enter a second number below 1,000,000:")
	print "The sum of the 2 numbers is:", number_1 + number_2

if operator == '-' then:
	print "Subtraction it is!"
	number_3 = input ("Please enter a number below 1,000,000:")
	number_4 = input ("Please enter a number below 1,000,000:")
	print "The sum of the 2 numbers is:" , number_3 - number_4

if operator == '*' then:
	print "Multiplication it is!"
	number_5 = input ("Please insert a number below 1,000,000:")
	number_6 = input ("Please insert a number below 1,000,000:")
	print "The sum of the 2 numers is:", number_5 * number_6

if operator == '/' then:
	print "Division it is!"
	number_7 = input ("Please insert a number below 1,000,000:")
	number_8 = input ("Please insert a number below 1,000,000:")
	print "The sum of the 2 numbers is:", number_7 / number_8

Thnx again fellas! :banana:

The error message was: File "program.py", Line 2

(Toggle Plain Text)

if operator == '+' then:

^
Invalid Syntax

I'm assuming that means that "then" cant go their, or one of those statement is wrong. If so, how can i change it to make it work? Is their another way to put it without getting to advanced?

Jessehk · Jan 17th, 2006, 11:24 PM

Just one quick suggestion: instead of getting the operator, and getting user input for every operator, why not get the operator, get the input, and then apply it to the operator?

eg:

get operator
get input
apply operator
print result

and the answer to your problem:

the correct form is :

(Toggle Plain Text)

if condition:
     #do stuff

Nebula · Jan 17th, 2006, 11:31 PM

@Jessehk
This is making my head hurt...Perhaps i'll just start over and take your advice.

coldDeath · Jan 18th, 2006, 1:29 AM

Nebula, you don't need the "then" keyword in Python, try removing it. :-D

So far its not a bad attempt, keep it up.

Sane · Jan 18th, 2006, 1:08 PM

Also certain things can be made easier (and faster) for you:

(Toggle Plain Text)

	number_7 = input ("Please insert a number below 1,000,000:")
	number_8 = input ("Please insert a number below 1,000,000:")
	print "The sum of the 2 numbers is:", number_7 / number_8

Becomes

(Toggle Plain Text)

	print "The sum of the 2 numbers is:", input ("Please insert a number below 1,000,000:") / input ("Please insert a number below 1,000,000:")

That's assuming you don't want to do anything with the variables after input.

Cerulean · Jan 18th, 2006, 4:02 PM

And don't use input. It's bad because it runs on eval on what it receives from the command line, meaning people can execute arbitary Python code through your program.
Use int(raw_input("Your prompt here... ")).
You may want to use a dictionary of operator functions to save you from coding a tonne of if statements, too.

Ooble · Jan 18th, 2006, 6:48 PM

Quote:

Originally Posted by Cerulean

And don't use input. It's bad because it runs on eval on what it receives from the command line, meaning people can execute arbitary Python code through your program.
Use int(raw_input("Your prompt here... ")).
You may want to use a dictionary of operator functions to save you from coding a tonne of if statements, too.

I wouldn't teach someone to do that until they were very comfortable with the language. It's just confusing.

Dietrich · Jan 19th, 2006, 1:17 PM

I like coldDeath's answer. The first thing I would improve then is the input() function. To bad a screwy thing like that is hanging around an otherwise perfect language!

Namingishard · Feb 7th, 2006, 5:02 PM

^^, yeah as said above i think you just need to take the Then out,

snipertomcat · Feb 7th, 2006, 5:10 PM

It might be better in this case to use functions.

Jan 17th, 2006, 11:20 PM	#1
Nebula Hobbyist Programmer Join Date: Oct 2005 Posts: 193 Rep Power: 3	Python calculator problem I really just winged this one, no tutorial help, no nothing. Just took my knowldge and tried something. Chances are, its completly wrong. I had some trouble running it and i thought it might be just some mundane error but if it is more than just a typo of incorrect statement, I would like to know what it is. Thnx a million. Its a, not-completed, calculator program ----> (Toggle Plain Text) operator = raw_input ("Please enter the prefered operator: +, -, , /") if operator == '+' then: print "Addition it is! number_1 = input ("Please insert a number below 1,000,000:") number_2 = input ("Please enter a second number below 1,000,000:") print "The sum of the 2 numbers is:", number_1 + number_2 if operator == '-' then: print "Subtraction it is!" number_3 = input ("Please enter a number below 1,000,000:") number_4 = input ("Please enter a number below 1,000,000:") print "The sum of the 2 numbers is:" , number_3 - number_4 if operator == '' then: print "Multiplication it is!" number_5 = input ("Please insert a number below 1,000,000:") number_6 = input ("Please insert a number below 1,000,000:") print "The sum of the 2 numers is:", number_5 * number_6 if operator == '/' then: print "Division it is!" number_7 = input ("Please insert a number below 1,000,000:") number_8 = input ("Please insert a number below 1,000,000:") print "The sum of the 2 numbers is:", number_7 / number_8 operator = raw_input ("Please enter the prefered operator: +, -, , /") if operator == '+' then: print "Addition it is! number_1 = input ("Please insert a number below 1,000,000:") number_2 = input ("Please enter a second number below 1,000,000:") print "The sum of the 2 numbers is:", number_1 + number_2 if operator == '-' then: print "Subtraction it is!" number_3 = input ("Please enter a number below 1,000,000:") number_4 = input ("Please enter a number below 1,000,000:") print "The sum of the 2 numbers is:" , number_3 - number_4 if operator == '' then: print "Multiplication it is!" number_5 = input ("Please insert a number below 1,000,000:") number_6 = input ("Please insert a number below 1,000,000:") print "The sum of the 2 numers is:", number_5 * number_6 if operator == '/' then: print "Division it is!" number_7 = input ("Please insert a number below 1,000,000:") number_8 = input ("Please insert a number below 1,000,000:") print "The sum of the 2 numbers is:", number_7 / number_8 Thnx again fellas! :banana: The error message was: File "program.py", Line 2 (Toggle Plain Text) if operator == '+' then: if operator == '+' then: ^ Invalid Syntax I'm assuming that means that "then" cant go their, or one of those statement is wrong. If so, how can i change it to make it work? Is their another way to put it without getting to advanced? __________________ When will Jesus bring the porkchops?

Jan 17th, 2006, 11:24 PM	#2
Jessehk The Oblivious One Join Date: May 2005 Location: Ontario, Canada Posts: 630 Rep Power: 4	Just one quick suggestion: instead of getting the operator, and getting user input for every operator, why not get the operator, get the input, and then apply it to the operator? eg: get operator get input apply operator print result and the answer to your problem: the correct form is : (Toggle Plain Text) if condition: #do stuff if condition: #do stuff __________________ Dr. Zoidberg: [ecstatic] I'm going to a movie... with FRIENDS!

Jan 17th, 2006, 11:31 PM	#3
Nebula Hobbyist Programmer Join Date: Oct 2005 Posts: 193 Rep Power: 3	@Jessehk This is making my head hurt...Perhaps i'll just start over and take your advice. __________________ When will Jesus bring the porkchops?

Jan 18th, 2006, 1:29 AM	#4
coldDeath Expert Programmer Join Date: Aug 2005 Location: UK Posts: 862 Rep Power: 3	Nebula, you don't need the "then" keyword in Python, try removing it. :-D So far its not a bad attempt, keep it up. __________________ Programming Tutorials - Linux Installation Guide - Learn Python - Learn C++ Got Slack? Join us at #programmingforums @ irc.freenode.net! My software never has bugs. It just develops random features.

Jan 18th, 2006, 1:08 PM	#5
Sane Programming Guru Join Date: Apr 2005 Posts: 1,799 Rep Power: 5	Also certain things can be made easier (and faster) for you: (Toggle Plain Text) number_7 = input ("Please insert a number below 1,000,000:") number_8 = input ("Please insert a number below 1,000,000:") print "The sum of the 2 numbers is:", number_7 / number_8 number_7 = input ("Please insert a number below 1,000,000:") number_8 = input ("Please insert a number below 1,000,000:") print "The sum of the 2 numbers is:", number_7 / number_8 Becomes (Toggle Plain Text) print "The sum of the 2 numbers is:", input ("Please insert a number below 1,000,000:") / input ("Please insert a number below 1,000,000:") print "The sum of the 2 numbers is:", input ("Please insert a number below 1,000,000:") / input ("Please insert a number below 1,000,000:") That's assuming you don't want to do anything with the variables after input.

Jan 18th, 2006, 4:02 PM	#6
Cerulean Professional Programmer Join Date: Apr 2005 Location: London, England Posts: 459 Rep Power: 4	And don't use input. It's bad because it runs on eval on what it receives from the command line, meaning people can execute arbitary Python code through your program. Use int(raw_input("Your prompt here... ")). You may want to use a dictionary of operator functions to save you from coding a tonne of if statements, too.

Jan 19th, 2006, 1:17 PM	#8
Dietrich Professional Programmer Join Date: Feb 2005 Posts: 434 Rep Power: 4	I like coldDeath's answer. The first thing I would improve then is the input() function. To bad a screwy thing like that is hanging around an otherwise perfect language! __________________ I looked it up on the Intergnats!

Feb 7th, 2006, 5:02 PM	#9
Namingishard Newbie Join Date: Feb 2006 Location: TX Posts: 23 Rep Power: 0	^^, yeah as said above i think you just need to take the Then out,

Feb 7th, 2006, 5:10 PM	#10
snipertomcat Programmer Join Date: Nov 2005 Location: Spring Valley, CA Posts: 52 Rep Power: 3	It might be better in this case to use functions.

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Programming Forums > Script Programming > Python

Python calculator problem