Re: [Tutor] Question on how to do exponents
On 07/02/12 01:01, Nate Lastname wrote: Exponents ... are **(or ^) Not quite the ^ operator is a bitwise XOR... 2^2 0 2^1 3 pow() is the other way to do exponents. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Question on how to do exponents
On 7 February 2012 13:49, Alan Gauld alan.ga...@btinternet.com wrote: On 07/02/12 01:01, Nate Lastname wrote: Exponents ... are **(or ^) Not quite the ^ operator is a bitwise XOR... 2^2 0 2^1 3 pow() is the other way to do exponents. Is is better to use pow() against **? -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ __**_ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/**mailman/listinfo/tutorhttp://mail.python.org/mailman/listinfo/tutor -- Sarma Tangirala, Class of 2012, Department of Information Science and Technology, College of Engineering Guindy - Anna University ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Question on how to do exponents
On 07/02/12 16:54, Sarma Tangirala wrote: Is is better to use pow() against **? I suspect ** will be faster since it doesn't have the function call overhead. But I haven't tried timing it. Feel free to do some tests and find out. Let us know how you get on! -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Question on how to do exponents
Sarma Tangirala wrote: Is is better to use pow() against **? Advantages of ** - it is shorter to type x**y vs pow(x, y) - being an operator, it is slightly faster than calling a function - you can't monkey-patch it Disadvantages of ** - being an operator, you can't directly use it as a function-object - it can't take three arguments - hard to google for ** - you can't monkey-patch it Advantages of pow() - it is a function, so you can pass it around as an object - three argument form - easy to call help(pow) to see documentation - easy to google for pow - can be monkey-patched Disadvantages of pow() - a tiny bit slower due to the function call - slightly longer to type - can be monkey-patched Weigh up the advantages and disadvantages of each, and make the call which is better for you. (My preference is to use the ** operator.) -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Question on how to do exponents
On 8 February 2012 00:01, Steven D'Aprano st...@pearwood.info wrote: Sarma Tangirala wrote: Is is better to use pow() against **? Advantages of ** - it is shorter to type x**y vs pow(x, y) - being an operator, it is slightly faster than calling a function - you can't monkey-patch it Disadvantages of ** - being an operator, you can't directly use it as a function-object - it can't take three arguments - hard to google for ** - you can't monkey-patch it Advantages of pow() - it is a function, so you can pass it around as an object - three argument form - easy to call help(pow) to see documentation - easy to google for pow - can be monkey-patched Disadvantages of pow() - a tiny bit slower due to the function call - slightly longer to type - can be monkey-patched Weigh up the advantages and disadvantages of each, and make the call which is better for you. (My preference is to use the ** operator.) A simple function call argument would have done! :D Thanks for the survey! Anyway, I was wondering about this, if internally pow() actually uses **. :P -- Steven __**_ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/**mailman/listinfo/tutorhttp://mail.python.org/mailman/listinfo/tutor -- Sarma Tangirala, Class of 2012, Department of Information Science and Technology, College of Engineering Guindy - Anna University ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Question on how to do exponents
On 02/07/2012 01:57 PM, Sarma Tangirala wrote: On 8 February 2012 00:01, Steven D'Apranost...@pearwood.info wrote: Sarma Tangirala wrote: Is is better to use pow() against **? Advantages of ** - it is shorter to type x**y vs pow(x, y) - being an operator, it is slightly faster than calling a function - you can't monkey-patch it Disadvantages of ** - being an operator, you can't directly use it as a function-object - it can't take three arguments - hard to google for ** - you can't monkey-patch it Advantages of pow() - it is a function, so you can pass it around as an object - three argument form - easy to call help(pow) to see documentation - easy to google for pow - can be monkey-patched Disadvantages of pow() - a tiny bit slower due to the function call - slightly longer to type - can be monkey-patched Weigh up the advantages and disadvantages of each, and make the call which is better for you. (My preference is to use the ** operator.) A simple function call argument would have done! :D Thanks for the survey! Anyway, I was wondering about this, if internally pow() actually uses **. :P I have no idea, but I'd assume so, unless there's a 3rd argument. At that point, the algorithm must change drastically. -- DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Question on how to do exponents
On 2/7/2012 1:57 PM, Sarma Tangirala wrote: Anyway, I was wondering about this, if internally pow() actually uses **. :P from dis import dis dis(lambda a,b:a**b) 1 0 LOAD_FAST0 (a) 3 LOAD_FAST1 (b) 6 BINARY_POWER 7 RETURN_VALUE dis(lambda a,b:pow(a,b)) 1 0 LOAD_GLOBAL 0 (pow) 3 LOAD_FAST0 (a) 6 LOAD_FAST1 (b) 9 CALL_FUNCTION2 12 RETURN_VALUE Now you know, and you know how to find out! To delve any deeper you'd have to inspect the c source for pow. I'd assume it uses the c exponent operator -- Bob Gailer 919-636-4239 Chapel Hill NC ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Question on how to do exponents
Exponents and remainder (modulus) are **(or ^) and % respectively. I.E.; d = a ** b (exponent) c = a % b (modulus) There you are! ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Question on how to do exponents
On Mon, Feb 06, 2012 at 04:54:57PM -0800, William Stewart wrote: Hello everyone, I am making a calculator and I need to know how to make it do exponents and remainders How can I input this info in python? Any help would be appreciated You can do exponents either with the ** operator or the pow() function: py 2**4 16 py pow(3, 5) 243 The pow() function is especially useful for advanced mathematics where you want to perform exponents modulo some base: py pow(3, 5, 2) 1 That is, it calculates the remainder when divided by 2 of 3**5 *without* needing to calculate 3**5 first. This is especially useful when the intermediate number could be huge: py pow(1357924680, 2468013579, 1256711) 418453L To get the remainder, use the % operator or the divmod() function: py 17 % 2 1 py divmod(17, 2) (8, 1) Hope this helps. P.S. please don't hijack threads by replying to an existing message, as it could lead to some people not seeing your email. It is better to start a new thread by using New Message, not with Reply. -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
