Re: Method question

...
>if field3.length >=3D 100
>   changer(field3)
>end

>def changer(fieldData)
> splitData =3D fieldData.split(",")
> splitData.each do |output|
> p output
>end

>What I would like to happen is when field3 for example is longer than
>100 and its data is passed to def charger, I want that method (def
>charger) to split the field on all commas and then return data to
>field3.

But changer returns nil (just output something)...



2009/7/29 steve <[e-mail]>

> Stuart Clarke wrote:
>
>> Hi all,
>>
> Hi Stuart
>
>
>> Struggling a little with the concept of an exercise I am doing.
>>
>> I have two Ruby methods, the first does a simple string replace the
>> second converts data to something else if the criteria is satisfied. See
>> example below
>>
>> def processer
>>  field1 =3D data[0]
>>  field2 =3D data[1]
>>  field3 =3D data[2]
>>  if field3.length < 100
>>  field3 =3D field3
>>  else
>>  changer(field3)
>>  end
>>  field4 =3D data[3]
>>  field5 =3D data[4]
>>  if field5.length < 100
>>  field5 =3D field5
>>  else
>>  changer(field5)
>>  end
>> end
>>
>>
>> def changer(fieldData)
>>  splitData =3D fieldData.split(",")
>>  splitData.each do |output|
>>  p output
>> end
>>
>> What I would like to happen is when field3 for example is longer than
>> 100 and its data is passed to def charger, I want that method (def
>> charger) to split the field on all commas and then return data to
>> field3.
>>
>> I could just put something like field3 =3D output, however when I get
>> other fields for example field5 this will not work and therefore I need
>> something generic that will give the data to the correct field.
>>
>> I hope this makes sense. Any help is much appreciated
>>
>> Regards
>>
>> Stuart
>>
>
> First off, assigning field3=3Dfield3 and field5=3Dfield5 is not terribly
> useful. A better way of doing this would be
>
> def processer
>  field1 =3D data[0]
>  field2 =3D data[1]
>  field3 =3D if data[2].length < 100
>              data[2]
>           else
>              changer(data[2])
>           end
>  field4 =3D data[3]
>  field5 =3D if data[4].length < 100
>              data[4]
>           else
>              changer(data[4])
>           end
> end
>
> Ruby can do parallel assignment so we can change the assignment to
>
> field1,field2,field3,field4,field5=3Ddata
>
> Then go back and change field3 and 5 if we need to - note the comparison
> needs to change as well.
>
> field3=3Dchanger(data[2]) if data[2].length !< 100
> field5=3Dchanger(data[4)) if data[4].length !< 100
>
> now for two repeats its probably not worth making a new method, but for 3
> I'd be tempted and for 4 I'd certainly write another method.  Lets do it
> anyway for practice.
>
> def check_n_change(x)
>  if x.length<100
>     x
>  else
>     changer(x)
>  end
> end
>
> The method returns the value of the last expression evaluated.
>
> Your original changer method was almost right. First you had a syntax err=
or
> as you need an end for the do and an end for the def.  But, the each bloc=
k
> is not needed anyway.  so changer becomes
>
> def changer(fieldData)
>   fieldData.split(',')
> end
>
> and the whole program is thus
>
> def processer
>  field1, field2, field3, field4, field5=3Ddata
>  check_n_change(field3)
>  check_n_change(field5)
> end
>
> def check_n_change(x)
>  if x.length<100
>     x
>  else
>     changer(x)
>  end
> end
>
> def changer(fieldData)
>  fieldData.split(',')
> end
>
> Of course you could roll changer back up into check_n_change at this leve=
l
> of complexity.
>
> Now, what would happen if data had more than 5 fields or fewer?  what if
> field3 was a number rather than a string?  You know your input data and s=
o
> what other checks are necessary.
>
> Hope this helps
>
> Steve.
>
>
>
>
>
>
>
>
>


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