Hi there, i am new to Smalltalk and Pharo and today, while trying out some examples, i observed an somewhat strange behaviour. I used this snippet from the pharo.org website: | numbers | numbers := Set new. 10 timesRepeat: [ numbers add: 100 atRandom ]. numbers explore. Using Pharo 3.0 on my Laptop with Manjaro Linux 32bit and copy pasting the snippet above into the workspace i get sometimes a set with 10 values, sometimes with 9 values and once a set with just 8 values. Using this snippet, just to test the timesRepeat message: 10 timesRepeat: [ Transcript show: (100 atRandom); cr. ]. i always get 10 values. Is the behaviour with the first snippet correct? Giving sometimes 10 or 9 or even 8 values. Or is it a bug? I would expect to always get 10 values in my set. By the way i am totally excited about your cool programming environment. Keep on the good work. I justed started to explore it and can say it is awesome to work with. Kind regards, Fabian
Hi Fabian, Welcome on board ;-) Set: I represent a set of objects without duplicates. so if you have the same number multiple times, it cannot be added more than once in the Set. replace Set by Bag (I represent an unordered collection of possibly duplicate elements.) and the size will always be 10. Best, Luc #Luc 2014-06-14 11:48 GMT+02:00 Fabian Boucsein <fabian.boucsein@googlemail.com>:
Hi there,
i am new to Smalltalk and Pharo and today, while trying out some examples, i observed an somewhat strange behaviour.
I used this snippet from the pharo.org website:
| numbers | numbers := Set new. 10 timesRepeat: [ numbers add: 100 atRandom ]. numbers explore.
Using Pharo 3.0 on my Laptop with Manjaro Linux 32bit and copy pasting the snippet above into the workspace i get sometimes a set with 10 values, sometimes with 9 values and once a set with just 8 values.
Using this snippet, just to test the timesRepeat message: 10 timesRepeat: [ Transcript show: (100 atRandom); cr. ]. i always get 10 values.
Is the behaviour with the first snippet correct? Giving sometimes 10 or 9 or even 8 values. Or is it a bug? I would expect to always get 10 values in my set.
By the way i am totally excited about your cool programming environment. Keep on the good work. I justed started to explore it and can say it is awesome to work with.
Kind regards, Fabian
In sets there can be only Unique nummers. So random produced a few of the same numbers. They get excluded from the set. Tim
Op 14 jun. 2014 om 11:48 heeft Fabian Boucsein <fabian.boucsein@googlemail.com> het volgende geschreven:
Hi there,
i am new to Smalltalk and Pharo and today, while trying out some examples, i observed an somewhat strange behaviour.
I used this snippet from the pharo.org website:
| numbers | numbers := Set new. 10 timesRepeat: [ numbers add: 100 atRandom ]. numbers explore.
Using Pharo 3.0 on my Laptop with Manjaro Linux 32bit and copy pasting the snippet above into the workspace i get sometimes a set with 10 values, sometimes with 9 values and once a set with just 8 values.
Using this snippet, just to test the timesRepeat message: 10 timesRepeat: [ Transcript show: (100 atRandom); cr. ]. i always get 10 values.
Is the behaviour with the first snippet correct? Giving sometimes 10 or 9 or even 8 values. Or is it a bug? I would expect to always get 10 values in my set.
By the way i am totally excited about your cool programming environment. Keep on the good work. I justed started to explore it and can say it is awesome to work with.
Kind regards, Fabian
Hi Fabien, As other already explained, you just discovered the marvelous Set collection. Hilaire Le 14/06/2014 11:48, Fabian Boucsein a écrit :
i am new to Smalltalk and Pharo and today, while trying out some examples, i observed an somewhat strange behaviour.
-- Dr. Geo http://drgeo.eu iStoa - https://launchpad.net/istoa
Hi Fabien and welcome, you just discovered this phenomenon: http://en.wikipedia.org/wiki/Birthday_problem and you can be proud having discovered it by yourself! Alain On Sun, Jun 15, 2014 at 12:12 AM, Hilaire Fernandes < hilaire.fernandes@gmail.com> wrote:
Hi Fabien,
As other already explained, you just discovered the marvelous Set collection.
Hilaire
Le 14/06/2014 11:48, Fabian Boucsein a écrit :
i am new to Smalltalk and Pharo and today, while trying out some examples, i observed an somewhat strange behaviour.
-- Dr. Geo http://drgeo.eu iStoa - https://launchpad.net/istoa
Alain, I love very much your cultural insight and I would like to see more examples like this one applied to Dr. Geo scripting or Smalltalk sketches. Personally, I don't have the time to both develop Dr. Geo *and* to investigate such examples; contributions like yours are more than welcome. Thanks Hilaire -- View this message in context: http://forum.world.st/A-question-about-sets-tp4763094p4764640.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
About the birthday problem, I already pulished something that I had exeperimented in the classroom, but it is in French: http://irem.univ-reunion.fr/spip.php?article618 (clic on "problème des anniversaires" tab). The idea is that if you add say 30 times a "365 atRandom" to a bag (instead of a set) it happens now and then that a number appear more than once. In this classroom, two students actually had the same birthday, and they were eager to know of it happens often, so that they were very active for this exercise. Happy reading ;-) Alain On Wed, Jun 25, 2014 at 12:10 PM, hilaire <hfern@free.fr> wrote:
Alain,
I love very much your cultural insight and I would like to see more examples like this one applied to Dr. Geo scripting or Smalltalk sketches. Personally, I don't have the time to both develop Dr. Geo *and* to investigate such examples; contributions like yours are more than welcome.
Thanks
Hilaire
-- View this message in context: http://forum.world.st/A-question-about-sets-tp4763094p4764640.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
Great! Now I wonder how it could be used within Dr. Geo. Thanks Hilaire Le 25/06/2014 18:33, Alain Busser a écrit :
About the birthday problem, I already pulished something that I had exeperimented in the classroom, but it is in French: http://irem.univ-reunion.fr/spip.php?article618 (clic on "problème des anniversaires" tab). The idea is that if you add say 30 times a "365 atRandom" to a bag (instead of a set) it happens now and then that a number appear more than once. In this classroom, two students actually had the same birthday, and they were eager to know of it happens often, so that they were very active for this exercise.
Happy reading ;-)
Alain
On Wed, Jun 25, 2014 at 12:10 PM, hilaire <hfern@free.fr <mailto:hfern@free.fr>> wrote:
Alain,
I love very much your cultural insight and I would like to see more examples like this one applied to Dr. Geo scripting or Smalltalk sketches. Personally, I don't have the time to both develop Dr. Geo *and* to investigate such examples; contributions like yours are more than welcome.
Thanks
Hilaire
-- View this message in context: http://forum.world.st/A-question-about-sets-tp4763094p4764640.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
-- Dr. Geo http://drgeo.eu iStoa - https://launchpad.net/istoa
About the use of sets I found another idea: Eratosthene's sieve. Basically you create a set containing all integers from 2 to, say, 200. Then, beginning with 2, you choose remove all multiples of the number you choose from the set. Then you go to the next number in the set and so on... The difficulty is to choose the right collection, as a set is not ordered and it is not easy to loop on the prime divisors... I made it on this article (near the middle): http://irem.univ-reunion.fr/spip.php?article742 Of course you can have the set of primes directly under Pharo with isPrime as we did here: http://www.epi.asso.fr/revue/articles/a1211b.htm (I had forgotten this) Alain On Thu, Jun 26, 2014 at 8:21 PM, Hilaire Fernandes < hilaire.fernandes@gmail.com> wrote:
Great! Now I wonder how it could be used within Dr. Geo.
Thanks
Hilaire
Le 25/06/2014 18:33, Alain Busser a écrit :
About the birthday problem, I already pulished something that I had exeperimented in the classroom, but it is in French: http://irem.univ-reunion.fr/spip.php?article618 (clic on "problème des anniversaires" tab). The idea is that if you add say 30 times a "365 atRandom" to a bag (instead of a set) it happens now and then that a number appear more than once. In this classroom, two students actually had the same birthday, and they were eager to know of it happens often, so that they were very active for this exercise.
Happy reading ;-)
Alain
On Wed, Jun 25, 2014 at 12:10 PM, hilaire <hfern@free.fr <mailto:hfern@free.fr>> wrote:
Alain,
I love very much your cultural insight and I would like to see more examples like this one applied to Dr. Geo scripting or Smalltalk sketches. Personally, I don't have the time to both develop Dr. Geo *and* to investigate such examples; contributions like yours are more than welcome.
Thanks
Hilaire
-- View this message in context: http://forum.world.st/A-question-about-sets-tp4763094p4764640.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
-- Dr. Geo http://drgeo.eu iStoa - https://launchpad.net/istoa
Why do you need a set for that? An array is enough. But please go on. Hilaire -- View this message in context: http://forum.world.st/A-question-about-sets-tp4763094p4765282.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
You're right but it should not have a fixed length because I want to remove numbers from it. I guess an SortedCollection is the best way to retrieve the next prime number. And the exercise is a good way to discover select and reject... Alain On Fri, Jun 27, 2014 at 1:41 PM, hilaire <hfern@free.fr> wrote:
Why do you need a set for that? An array is enough. But please go on.
Hilaire
-- View this message in context: http://forum.world.st/A-question-about-sets-tp4763094p4765282.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
Fun French Smalltalk. Il y a une version dispo? Phil Le 25 juin 2014 18:33, "Alain Busser" <alain.busser@gmail.com> a écrit :
About the birthday problem, I already pulished something that I had exeperimented in the classroom, but it is in French: http://irem.univ-reunion.fr/spip.php?article618 (clic on "problème des anniversaires" tab). The idea is that if you add say 30 times a "365 atRandom" to a bag (instead of a set) it happens now and then that a number appear more than once. In this classroom, two students actually had the same birthday, and they were eager to know of it happens often, so that they were very active for this exercise.
Happy reading ;-)
Alain
On Wed, Jun 25, 2014 at 12:10 PM, hilaire <hfern@free.fr> wrote:
Alain,
I love very much your cultural insight and I would like to see more examples like this one applied to Dr. Geo scripting or Smalltalk sketches. Personally, I don't have the time to both develop Dr. Geo *and* to investigate such examples; contributions like yours are more than welcome.
Thanks
Hilaire
-- View this message in context: http://forum.world.st/A-question-about-sets-tp4763094p4764640.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
oui, c'est ici: http://irem.univ-reunion.fr/spip.php?rubrique140 Avec un lien de téléchargement: https://dl.dropbox.com/u/10996692/MathsOntologie.zip btw I still plan to port it to Pharo3... Alain On Sat, Jun 28, 2014 at 10:24 AM, phil@highoctane.be <phil@highoctane.be> wrote:
Fun French Smalltalk.
Il y a une version dispo?
Phil Le 25 juin 2014 18:33, "Alain Busser" <alain.busser@gmail.com> a écrit :
About the birthday problem, I already pulished something that I had
exeperimented in the classroom, but it is in French: http://irem.univ-reunion.fr/spip.php?article618 (clic on "problème des anniversaires" tab). The idea is that if you add say 30 times a "365 atRandom" to a bag (instead of a set) it happens now and then that a number appear more than once. In this classroom, two students actually had the same birthday, and they were eager to know of it happens often, so that they were very active for this exercise.
Happy reading ;-)
Alain
On Wed, Jun 25, 2014 at 12:10 PM, hilaire <hfern@free.fr> wrote:
Alain,
I love very much your cultural insight and I would like to see more examples like this one applied to Dr. Geo scripting or Smalltalk sketches. Personally, I don't have the time to both develop Dr. Geo *and* to investigate such examples; contributions like yours are more than welcome.
Thanks
Hilaire
-- View this message in context: http://forum.world.st/A-question-about-sets-tp4763094p4764640.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.
Steph, It could be nice to add Alain's MathsOntologie as a success story, a nice example about what you can easily do with Pharo in the education sector Hilaire Le 28/06/2014 09:17, Alain Busser a écrit :
oui, c'est ici: http://irem.univ-reunion.fr/spip.php?rubrique140
Avec un lien de téléchargement: https://dl.dropbox.com/u/10996692/MathsOntologie.zip
btw I still plan to port it to Pharo3...
-- Dr. Geo http://drgeo.eu iStoa - https://launchpad.net/istoa
participants (9)
-
Alain Busser -
Ben Coman -
Fabian Boucsein -
hilaire -
Hilaire Fernandes
-
Hilaire Fernandes -
Luc Fabresse -
phil＠highoctane.be -
Tim Hendriks