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Re: [Pharo-users] what must be instead of the ??

by Peter Uhnak

> > but how do I find now the answer do I have to do something like puzzle1 > stepChanges detectIndex ? How do you mean? It would be the same santaFloorOnBasement "calculates which step take Santa to the basement" stepChanges := input collect: [ :c | floor := floor + (c = '(' ifTrue: [ 1 ] ifFalse: [ -1 ]). floor ]. stepChanges detectIndex: [ :each | each = -1 ] ifNone: [ 'invalid input yo' ]. then I see this error message : Improper store to indexable object. Because earlier you were comparing strings and not characters, I assumed your input was an array of strings like #('(' '(' '('). but you can fix that by changing `input collect:` -> `input asArray collect:` and `c = '('` -> `c = $(`. I have thought of something but I found it wierd that you do steps when you > have already the answer. That is indeed true, personally I would decide based on how often the method is called and how large the input is. Because this cumulative change makes it much easier to debug any issues... and usually I prefer debuggability over performance (unless it is an actual bottleneck). Peter On Fri, Nov 9, 2018 at 6:38 PM Gabriel Cotelli <g.cotelli(a)gmail.com> wrote: > It's bug in the collect: implementation used in String. I've opened > https://pharo.fogbugz.com/f/cases/22652/collect-over-Strings-is-broken > > On Fri, Nov 9, 2018 at 2:17 PM Roelof Wobben <r.wobben(a)home.nl> wrote: > >> hmm. >> >> When I try this on P7 >> >> |input stepChanges floor| >> input := '((('. >> floor := 0. >> stepChanges := input collect: [ :c | >> floor := floor + (c = '(' ifTrue: [ 1 ] ifFalse: [ -1 ]). >> floor >> ]. >> >> stepChanges detectIndex: [ :each | each = -1 ] ifNone: [ 'invalid input >> yo' ]. >> >> then I see this error message : Improper store to indexable object. >> >> Roelof >> >> >> Op 9-11-2018 om 17:39 schreef Roelof Wobben: >> >> stepChanges := input collect: [ :c | >> floor := floor + (c = '(' ifTrue: [ 1 ] ifFalse: [ -1 ]). >> floor >> ]. >> >> stepChanges detectIndex: [ :each | each = -1 ] ifNone: [ 'invalid input >> yo' ]. >> >> >>

Nov. 9, 2018

Re: [Pharo-users] what must be instead of the ??

by Alistair Grant

On Fri, 9 Nov 2018 at 18:38, Gabriel Cotelli <g.cotelli(a)gmail.com> wrote: > > It's bug in the collect: implementation used in String. I've opened https://pharo.fogbugz.com/f/cases/22652/collect-over-Strings-is-broken Strings store characters, not integers, so change your example to: 'aa' collect: [ :a | $1 ] and you'll see that (I think) it is working as expected. You could do: 'aa' collect: [ :a | 1 ] as: Array. Roelof, revisit your example, taking the above in to account :-) HTH, Alistair

Nov. 9, 2018

Re: [Pharo-users] what must be instead of the ??

by Gabriel Cotelli

It's bug in the collect: implementation used in String. I've opened https://pharo.fogbugz.com/f/cases/22652/collect-over-Strings-is-broken On Fri, Nov 9, 2018 at 2:17 PM Roelof Wobben <r.wobben(a)home.nl> wrote: > hmm. > > When I try this on P7 > > |input stepChanges floor| > input := '((('. > floor := 0. > stepChanges := input collect: [ :c | > floor := floor + (c = '(' ifTrue: [ 1 ] ifFalse: [ -1 ]). > floor > ]. > > stepChanges detectIndex: [ :each | each = -1 ] ifNone: [ 'invalid input > yo' ]. > > then I see this error message : Improper store to indexable object. > > Roelof > > > Op 9-11-2018 om 17:39 schreef Roelof Wobben: > > stepChanges := input collect: [ :c | > floor := floor + (c = '(' ifTrue: [ 1 ] ifFalse: [ -1 ]). > floor > ]. > > stepChanges detectIndex: [ :each | each = -1 ] ifNone: [ 'invalid input > yo' ]. > > >

Nov. 9, 2018

Re: [Pharo-users] what must be instead of the ??

by Roelof Wobben

Nov. 9, 2018

Re: [Pharo-users] what must be instead of the ??

by Roelof Wobben

Nov. 9, 2018

Re: [Pharo-users] what must be instead of the ??

by Peter Uhnak

On Fri, Nov 9, 2018 at 1:26 PM Roelof Wobben <r.wobben(a)home.nl> wrote: > Thanks all. > > This code seems to do the job > > santaFloorOnBasement > "calculates which step take Santa to the basement" > | index| > index := 1. > [floor ~= -1 ] whileTrue: > [ floor := ((input at: index) = '(' ) > ifTrue: [ floor + 1 ] > ifFalse: [ floor - 1 ]. > index := index + 1 ]. > > ^ index -1 > You can also think of it from the perspective of data processing and not instruction coding (and mangling of indexes). stepChanges := input collect: [ :c | floor := floor + (c = '(' ifTrue: [ 1 ] ifFalse: [ -1 ]). floor ]. stepChanges detectIndex: [ :each | each = -1 ] ifNone: [ 'invalid input yo' ]. Peter

Nov. 9, 2018

Re: [Pharo-users] what must be instead of the ??

by Roelof Wobben

Nov. 9, 2018

Re: [Pharo-users] what must be instead of the ??

by Ben Coman

On Fri, 9 Nov 2018 at 15:25, Roelof Wobben <r.wobben(a)home.nl> wrote: > Hello, > > I try to solve a adventofcode challenge where I must find out when santa > is first at the basement. the floor is there -1. > So I thought I use a while loop like this : > > santaFloorOnBasement > "calculates which step take Santa to the basement" > | index| > index := 1. > ??? when: (floor >=0 ) do: > [ floor := (input at: index = '(' ) > ifTrue: [ floor + 1 ] > ifFalse: [ floor - 1 ]. > index := index + 1 ]. > > but I cannot find out what must be instead of the ?? > I've never used #when:do: so I can't comment on that. I'd be using #whileTrue: which looks like this... [ condition block ] whileTrue: [ action block ] <<< ??? when: (floor >=0 ) do: >>> [floor>=0] whileTrue: For further examples review the "senders" of #whileTrue: i.e. highlight then press <CTRL-N> on MS Windows > index is the index of the string which has to start with a 1. > floor and input are both instance variables. floor contains the current > floor and input the input of the challenge. > > Can someone help me figure this out so the next time I can do this on my > own. > btw you have a problem here... floor := (input at: index = '(' ) Its not doing what you think and you'll get "Error: only integers should be used as indices" Consider you that two messages are being sent: * the keyword message... #at: * the binary message.... #= Homework :)... what is the third type of message and the evaluation priority of all three. Homework 2... Review the "implementors" of message #= <CTRL-M> on MS Windows cheers -ben P.S. As it current stands, you'll get a "SubscriptOutOfBounds" error if the input ends before Santa gets to the basement. An exercise, fix that using the existing loop. Then consider using an iterator... input do: [ :bracket | (bracket = $( ) ifTrue: [ floor := floor + 1 ] . (bracket = $( ) ifTrue: [ floor := floor + 1 ] ]. and maybe something else for you to experiment with... movement := Dictionary new. movement at: $( put: 1. movement at: $) put: -1. input do: [ :char | floor := floor + (movement at: char ifAbsent: [0]) ]. cheers -ben

Nov. 9, 2018

Re: [Pharo-users] what must be instead of the ??

by Tim Mackinnon

To add to what Joachim has said, and to help you help yourself, look at what methods are implemented in BlockClosure and Boolean and see how things work (the code is there for you to understand it quite easily - there is little magic going on). You can find all kinds of interesting and helpful things and can even implement your own if you ever want to. Tim Sent from my iPhone > On 9 Nov 2018, at 16:02, Joachim Tuchel <jtuchel(a)objektfabrik.de> wrote: > > So I guess that floor > 0 is your condition, right? In Smalltalk, the idea is that you evaluate the condition and ask the result of it (usually true or false) to do something. > > Right so far? That would mean the receiver of your wanted message is either the result of the evaluation or or a Block which will be evaluated in a construct like ifTrue: or something like whileTrue: > > HTH > > Joachim > > > >> Am 09.11.2018 um 08:24 schrieb Roelof Wobben <r.wobben(a)home.nl>: >> >> Hello, >> >> I try to solve a adventofcode challenge where I must find out when santa is first at the basement. the floor is there -1. >> So I thought I use a while loop like this : >> >> santaFloorOnBasement >> "calculates which step take Santa to the basement" >> | index| >> index := 1. >> ??? when: (floor >=0 ) do: >> [ floor := (input at: index = '(' ) >> ifTrue: [ floor + 1 ] >> ifFalse: [ floor - 1 ]. >> index := index + 1 ]. >> >> but I cannot find out what must be instead of the ?? >> >> index is the index of the string which has to start with a 1. >> floor and input are both instance variables. floor contains the current floor and input the input of the challenge. >> >> Can someone help me figure this out so the next time I can do this on my own. >> >> Roelof >> >> >> > >

Nov. 9, 2018

Re: [Pharo-users] what must be instead of the ??

by Joachim Tuchel

So I guess that floor > 0 is your condition, right? In Smalltalk, the idea is that you evaluate the condition and ask the result of it (usually true or false) to do something. Right so far? That would mean the receiver of your wanted message is either the result of the evaluation or or a Block which will be evaluated in a construct like ifTrue: or something like whileTrue: HTH Joachim > Am 09.11.2018 um 08:24 schrieb Roelof Wobben <r.wobben(a)home.nl>: > > Hello, > > I try to solve a adventofcode challenge where I must find out when santa is first at the basement. the floor is there -1. > So I thought I use a while loop like this : > > santaFloorOnBasement > "calculates which step take Santa to the basement" > | index| > index := 1. > ??? when: (floor >=0 ) do: > [ floor := (input at: index = '(' ) > ifTrue: [ floor + 1 ] > ifFalse: [ floor - 1 ]. > index := index + 1 ]. > > but I cannot find out what must be instead of the ?? > > index is the index of the string which has to start with a 1. > floor and input are both instance variables. floor contains the current floor and input the input of the challenge. > > Can someone help me figure this out so the next time I can do this on my own. > > Roelof > > >

Nov. 9, 2018