go to the end of a loop

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go to the end of a loop

Joseph Alotta
Greetings,

I have this code:

******

read
        "read the category file into the dictionary
        the first item is the category, the rest of the line are payees
       
        office expense|home depot|staples|costco
        groceries|natures best|jewel|trader joes|fresh thyme
        "

| f line |
f := FileStream oldFileNamed: myfile.

[(line := f nextLine) notNil] whileTrue: [        | array cat payees |
               
                           array := line  findTokens: $| escapedBy:  Character tab .

                                        cat := array first.
                                        payees := array reject: [ :i | i = cat ].   "rest of the line"
                                       
                                        payees do:  [ :p |   mydict at: (p withBlanksCondensed) put: (cat withBlanksCondensed)].
                           ].


f close.

*********

I am getting some blank lines in the data file.  Lines with just a Character cr.  I was wondering how to handle that.  In other languages, there is a break for the loop, to go to the end.  I can do:

(line size < 2) ifTrue: [ f nextLine.].

But that would interfere with the notNil idiom at the end of the file.  So where do I put this.  Is there a common way to jump to the end?


Sincerely,


Joe.





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Re: go to the end of a loop

jelena

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go to the end of a loop

Louis LaBrunda
In reply to this post by Joseph Alotta
Hi Joe,

Better than checking for #nextLine answering nil, I think you can send the file stream #atEnd
to see if there is any more data.  You would then use a #whileFalse: and move the #nextLine
call into the second block of the whileFalse:.  Then test for empty lines with something like:
(line size < 2) ifFalse: [...putting all the code that does the work on a line with data in
here...].

Lou

PS.   If this is not a school project, we can be of more help, we just don't like doing
students projects for them as they learn more with just a few hints and not real code.

On Mon, 25 Apr 2016 10:16:33 -0500, Joseph Alotta <[hidden email]> wrote:

>Greetings,
>
>I have this code:
>
>******
>
>read
> "read the category file into the dictionary
> the first item is the category, the rest of the line are payees
>
> office expense|home depot|staples|costco
> groceries|natures best|jewel|trader joes|fresh thyme
> "
>
>| f line |
>f := FileStream oldFileNamed: myfile.
>
>[(line := f nextLine) notNil] whileTrue: [        | array cat payees |
>
>                   array := line  findTokens: $| escapedBy:  Character tab .
>
> cat := array first.
> payees := array reject: [ :i | i = cat ].   "rest of the line"
>
> payees do:  [ :p |   mydict at: (p withBlanksCondensed) put: (cat withBlanksCondensed)].
>                   ].
>
>
>f close.
>
>*********
>
>I am getting some blank lines in the data file.  Lines with just a Character cr.  I was wondering how to handle that.  In other languages, there is a break for the loop, to go to the end.  I can do:
>
>(line size < 2) ifTrue: [ f nextLine.].
>
>But that would interfere with the notNil idiom at the end of the file.  So where do I put this.  Is there a common way to jump to the end?
>
>
>Sincerely,
>
>
>Joe.
--
Louis LaBrunda
Keystone Software Corp.
SkypeMe callto://PhotonDemon

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Re: go to the end of a loop

Joseph Alotta
Hi Louis,

This is not a school project.  I was looking for a local tutor but could find none.  So this is me doing this instead of working crossword puzzles or sudukos.

So your advice would be:

(f atEnd) whileFalse: [  
                line := f nextLine

                (line size < 2) ifFalse:  [ “process line”].

].


Sincerely,

Joe.





> On Apr 25, 2016, at 10:06 AM, Louis LaBrunda [via Smalltalk] <[hidden email]> wrote:
>
> Hi Joe,
>
> Better than checking for #nextLine answering nil, I think you can send the file stream #atEnd
> to see if there is any more data.  You would then use a #whileFalse: and move the #nextLine
> call into the second block of the whileFalse:.  Then test for empty lines with something like:
> (line size < 2) ifFalse: [...putting all the code that does the work on a line with data in
> here...].
>
> Lou
>
> PS.   If this is not a school project, we can be of more help, we just don't like doing
> students projects for them as they learn more with just a few hints and not real code.
>
> On Mon, 25 Apr 2016 10:16:33 -0500, Joseph Alotta <[hidden email]> wrote:
>
> >Greetings,
> >
> >I have this code:
> >
> >******
> >
> >read
> > "read the category file into the dictionary
> > the first item is the category, the rest of the line are payees
> >
> > office expense|home depot|staples|costco
> > groceries|natures best|jewel|trader joes|fresh thyme
> > "
> >
> >| f line |
> >f := FileStream oldFileNamed: myfile.
> >
> >[(line := f nextLine) notNil] whileTrue: [        | array cat payees |
> >
> >                  array := line  findTokens: $| escapedBy:  Character tab .
> >
> > cat := array first.
> > payees := array reject: [ :i | i = cat ].   "rest of the line"
> >
> > payees do:  [ :p |   mydict at: (p withBlanksCondensed) put: (cat withBlanksCondensed)].
> >                  ].
> >
> >
> >f close.
> >
> >*********
> >
> >I am getting some blank lines in the data file.  Lines with just a Character cr.  I was wondering how to handle that.  In other languages, there is a break for the loop, to go to the end.  I can do:
> >
> >(line size < 2) ifTrue: [ f nextLine.].
> >
> >But that would interfere with the notNil idiom at the end of the file.  So where do I put this.  Is there a common way to jump to the end?
> >
> >
> >Sincerely,
> >
> >
> >Joe.
> --
> Louis LaBrunda
> Keystone Software Corp.
> SkypeMe callto://PhotonDemon
>
> _______________________________________________
> Beginners mailing list
> [hidden email]
> http://lists.squeakfoundation.org/mailman/listinfo/beginners
>
>
> If you reply to this email, your message will be added to the discussion below:
> http://forum.world.st/go-to-the-end-of-a-loop-tp4891930p4891939.html
> To start a new topic under Squeak - Beginners, email [hidden email]
> To unsubscribe from Squeak - Beginners, click here.
> NAML

cbc
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Re: go to the end of a loop

cbc
Yes, except #whileFalse: only works against blocks. So:
     [f atEnd] whileFalse: [   

On Mon, Apr 25, 2016 at 9:59 AM, Joseph Alotta <[hidden email]> wrote:
Hi Louis,

This is not a school project.  I was looking for a local tutor but could find none.  So this is me doing this instead of working crossword puzzles or sudukos.

So your advice would be:

(f atEnd) whileFalse: [  
                line := f nextLine

                (line size < 2) ifFalse:  [ “process line”].

].


Sincerely,

Joe.





> On Apr 25, 2016, at 10:06 AM, Louis LaBrunda [via Smalltalk] <[hidden email]> wrote:
>
> Hi Joe,
>
> Better than checking for #nextLine answering nil, I think you can send the file stream #atEnd
> to see if there is any more data.  You would then use a #whileFalse: and move the #nextLine
> call into the second block of the whileFalse:.  Then test for empty lines with something like:
> (line size < 2) ifFalse: [...putting all the code that does the work on a line with data in
> here...].
>
> Lou
>
> PS.   If this is not a school project, we can be of more help, we just don't like doing
> students projects for them as they learn more with just a few hints and not real code.
>
> On Mon, 25 Apr 2016 10:16:33 -0500, Joseph Alotta <[hidden email]> wrote:

>
> >Greetings,
> >
> >I have this code:
> >
> >******
> >
> >read
> > "read the category file into the dictionary
> > the first item is the category, the rest of the line are payees
> >
> > office expense|home depot|staples|costco
> > groceries|natures best|jewel|trader joes|fresh thyme
> > "
> >
> >| f line |
> >f := FileStream oldFileNamed: myfile.
> >
> >[(line := f nextLine) notNil] whileTrue: [        | array cat payees |
> >
> >                  array := line  findTokens: $| escapedBy:  Character tab .
> >
> > cat := array first.
> > payees := array reject: [ :i | i = cat ].   "rest of the line"
> >
> > payees do:  [ :p |   mydict at: (p withBlanksCondensed) put: (cat withBlanksCondensed)].
> >                  ].
> >
> >
> >f close.
> >
> >*********
> >
> >I am getting some blank lines in the data file.  Lines with just a Character cr.  I was wondering how to handle that.  In other languages, there is a break for the loop, to go to the end.  I can do:
> >
> >(line size < 2) ifTrue: [ f nextLine.].
> >
> >But that would interfere with the notNil idiom at the end of the file.  So where do I put this.  Is there a common way to jump to the end?
> >
> >
> >Sincerely,
> >
> >
> >Joe.
> --
> Louis LaBrunda
> Keystone Software Corp.
> SkypeMe <a href="callto://PhotonDemon" target="_blank">callto://PhotonDemon
>
> _______________________________________________
> Beginners mailing list
> [hidden email]
> http://lists.squeakfoundation.org/mailman/listinfo/beginners
>
>
> If you reply to this email, your message will be added to the discussion below:
> http://forum.world.st/go-to-the-end-of-a-loop-tp4891930p4891939.html
> To start a new topic under Squeak - Beginners, email [hidden email]
> To unsubscribe from Squeak - Beginners, click here.
> NAML



View this message in context: Re: go to the end of a loop
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Re: go to the end of a loop

Balázs Kósi
Hi Joseph!

Here is my take on your problem:

categoriesByPayees
 := Dictionary new.
FileStream readOnlyFileNamed: 'payees-by-categories.txt' do: [ :file |
    
" With #readOnlyFileNamed:do: you don't have to worry about closing the file,
    it ensures that #close is sent to the file, even if you leave the block through an Exception. "

    
[ file atEnd ] whileFalse: [
        
| parts |
        
parts := (file nextLine findTokens: $| escapedBy: Character tab)
            
collect: #withBlanksCondensed.
        
" We collect the parts #withBlanksCondensed, so we don't have to call it repeatedly in the loop.
        You can use unary selectors in place of blocks with one argument. You may look at the implementation
        of Collection >> #collect: and Symbol >> #value: to find out why. I'm not sure what you really want is
        #findTokens:escapedBy:, it cuts the string along | characters if they are not preceded by a tab."
        
parts size > 1 ifTrue: [ 
            
" We skip blank lines or categories without at least one payee. "
            
| category |
            
category := parts first.
            
parts allButFirstDo: [ :payee |
                
(categoriesByPayees
                    
at: payee
                    
ifAbsentPut: [ OrderedCollection new ]) add: category
                    
" Your implementation only remembers the last category encountered for a payee.
                    We can collect all the categories. "
 ] ] ] ]

Cheers, Balázs

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Re: go to the end of a loop

Joseph Alotta
thank you.  i will studying this.

sincerely,

Joe.



> On Apr 26, 2016, at 7:48 AM, Balázs Kósi [via Smalltalk] <[hidden email]> wrote:
>
> categoriesByPayees := Dictionary new.
> FileStream readOnlyFileNamed: 'payees-by-categories.txt' do: [ :file |
>     " With #readOnlyFileNamed:do: you don't have to worry about closing the file,
>     it ensures that #close is sent to the file, even if you leave the block through an Exception. "
>     [ file atEnd ] whileFalse: [
>         | parts |
>         parts := (file nextLine findTokens: $| escapedBy: Character tab)
>             collect: #withBlanksCondensed.
>         " We collect the parts #withBlanksCondensed, so we don't have to call it repeatedly in the loop.
>         You can use unary selectors in place of blocks with one argument. You may look at the implementation
>         of Collection >> #collect: and Symbol >> #value: to find out why. I'm not sure what you really want is
>         #findTokens:escapedBy:, it cuts the string along | characters if they are not preceded by a tab."
>         parts size > 1 ifTrue: [
>             " We skip blank lines or categories without at least one payee. "
>             | category |
>             category := parts first.
>             parts allButFirstDo: [ :payee |
>                 (categoriesByPayees
>                     at: payee
>                     ifAbsentPut: [ OrderedCollection new ]) add: category
>                     " Your implementation only remembers the last category encountered for a payee.
>                     We can collect all the categories. " ] ] ] ]​

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