Re: [Tutor] Beginner - understanding randint arguments
On 02/15/2014 11:25 AM, Marc Eymard wrote: Hello Tutor, I need to generate a random integer between 0 and 100. The range is supposed to be adjusted by my two variables: low_range and high_range. The logic of using the variables as part of the function arguments is to manage to get a smaller range each time the function is called _excluding_ the possible repeat of the return value of randint. Here is what happens in my script: import random low_range = -1 high_range = 101 random.randint(low_range + 1, high_range - 1) 56 low_range -1 high_range 101* * I was rather expecting: low_range 0 high_range 100 Can somebody explain why both low_range and high_range are still returning their initial values ? Thanks, Marc* * The variables low_range and high_range are not modified. The arguments to random.randint do not change the initial values of the variables, only the actual values passed. -- Jay Lozier jsloz...@gmail.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Beginner - understanding randint arguments
On 15/02/14 16:25, Marc Eymard wrote: Here is what happens in my script: import random low_range = -1 high_range = 101 random.randint(low_range + 1, high_range - 1) 56 low_range -1 high_range 101* I was rather expecting: low_range 0 high_range 100 Really? Why? You never change low_range or high_range so why would their values change? The help() for randint says: randint(self, a, b) method of random.Random instance Return random integer in range [a, b], including both end points. So the function doesn't change the values either it just returns a random number between them. Can somebody explain why both low_range and high_range are still returning their initial values ? Because you didn't change them. When you called randint you passed in two expressions: low_range+1 and high_range-1 which Python evaluated as 0 and 100. But that did not change your variable values in any way, it just created new values that were passed into randint() as 'a' and 'b' respectively. -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/ http://www.flickr.com/photos/alangauldphotos ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Beginner - understanding randint arguments
On Sat, Feb 15, 2014 at 04:25:34PM +, Marc Eymard wrote: Can somebody explain why both low_range and high_range are still returning their initial values ? Because you haven't changed either of them. Imagine the chaos if every time you did arithmetic on a variable, Python changed the variable: x = 1 y = x + 100 What is the value of y? 101, correct? What is the value of x? It should still be 1, not 101. The same applies when you get rid of the y = and just pass it to a function: x = 1 some_function(x + 100) What's the value of x? It needs to be 1, because you haven't changed it. The only way to change x is to explicitly change it: x = x + 100 -- Steven ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
