[newbie] Array of Arrays (JRuby raise an exception)

ruby-talk
1

JRuby raise an exception with the following code :

columnFields = fieldsHash.keys
columnHeaders = fieldsHash.values
selectedFields = fieldsHash.join_keys ", "

datas = Array.new
myRows = query.executeQuery("SELECT " + selectedFields + " FROM " + tbl

  • “;”)
    while myRows.next()
    myCols = Array.new
    fieldsHash.keys.each {|fhk| myCols << myRows.getString(fhk) }
    datas << myCols
    end

model = Table::DefaultTableModel.new

printMethods(model)

print datas, “\n”

model.setDataVector(datas, columnHeaders)
$table.setModel(model)

i suspect de line :

datas << myCols flatten the Array “datas” which has to be an Array of
Arrays that’s to say each element of the Array “datas” has to be an
Array itself (being a set of columns from a database)

the equivalent in Java/BeanShell being Vector of Vectors.

i’m sure (print out) all datas are OK but the structure of them.

then the question is to know if the line “datas << myCols” returns an
Array of Array or simply an concataneted Array ???

···

–
yt

2

I’m sure now datas is an Array of Arrays (by printing size) the the
error is comin from elsewhere…

···

Yvon Thoraval yvon.thoravalNO-SPAM@free.fr wrote:

then the question is to know if the line “datas << myCols” returns an
Array of Array or simply an concataneted Array ???

–
yt

3

[Yvon Thoraval yvon.thoravalNO-SPAM@free.fr, 2004-03-30 10.44 CEST]

JRuby raise an exception with the following code :

You should give more information if you want help: what exception,
which line, etc.

columnFields = fieldsHash.keys
columnHeaders = fieldsHash.values
selectedFields = fieldsHash.join_keys ", "

datas = Array.new
myRows = query.executeQuery("SELECT " + selectedFields + " FROM " + tbl

  • “;”)
    while myRows.next()
    myCols = Array.new
    fieldsHash.keys.each {|fhk| myCols << myRows.getString(fhk)}

If fieldsHash is a normal ruby Hash, the order of the keys is
arbitrary.

[…]

i suspect de line :

datas << myCols flatten the Array “datas” which has to be an Array of
Arrays that’s to say each element of the Array “datas” has to be an
Array itself (being a set of columns from a database)

the equivalent in Java/BeanShell being Vector of Vectors.

i’m sure (print out) all datas are OK but the structure of them.

then the question is to know if the line “datas << myCols” returns an
Array of Array or simply an concataneted Array ???

To see what is in a variable, use ‘p’ or #inspect. ‘p’ prints,
#inspect returns a string.

$ ruby -e ‘a=[“1”,2,[“3”]]; p a; puts a.inspect’
[“1”, 2, [“3”]]
[“1”, 2, [“3”]]

Good luck.

4

If fieldsHash is a normal ruby Hash, the order of the keys is
arbitrary.

no, it is a so called “OrderedHash”…

To see what is in a variable, use ‘p’ or #inspect. ‘p’ prints,
#inspect returns a string.

$ ruby -e ‘a=[“1”,2,[“3”]]; p a; puts a.inspect’
[“1”, 2, [“3”]]
[“1”, 2, [“3”]]

ok, tanxs, this will help me a lot seeing the structure of an array
instead of the flatten way used by print…

by the way, i’ve found my error, i had to use JavaUtil::Vector instead
of Ruby Arrays (i’m using JRuby to set a java-swing table model…)

···

Carlos angus@quovadis.com.ar wrote:

yt