44 lines
1.4 KiB
Ruby
44 lines
1.4 KiB
Ruby
J2justifier = {Left: :ljust, Right: :rjust, Center: :center}
|
|
|
|
=begin
|
|
Justify columns of textual tabular input where the record separator is the newline
|
|
and the field separator is a 'dollar' character.
|
|
justification can be Symbol; (:Left, :Right, or :Center).
|
|
|
|
Return the justified output as a string
|
|
=end
|
|
def aligner(infile, justification = :Left)
|
|
fieldsbyrow = infile.map {|line| line.strip.split('$')}
|
|
# pad to same number of fields per record
|
|
maxfields = fieldsbyrow.map(&:length).max
|
|
fieldsbyrow.map! {|row| row + ['']*(maxfields - row.length)}
|
|
# calculate max fieldwidth per column
|
|
colwidths = fieldsbyrow.transpose.map {|column|
|
|
column.map(&:length).max
|
|
}
|
|
# pad fields in columns to colwidth with spaces
|
|
justifier = J2justifier[justification]
|
|
fieldsbyrow.map {|row|
|
|
row.zip(colwidths).map {|field, width|
|
|
field.send(justifier, width)
|
|
}.join(" ")
|
|
}.join("\n")
|
|
end
|
|
|
|
require 'stringio'
|
|
|
|
textinfile = <<END
|
|
Given$a$text$file$of$many$lines,$where$fields$within$a$line$
|
|
are$delineated$by$a$single$'dollar'$character,$write$a$program
|
|
that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$
|
|
column$are$separated$by$at$least$one$space.
|
|
Further,$allow$for$each$word$in$a$column$to$be$either$left$
|
|
justified,$right$justified,$or$center$justified$within$its$column.
|
|
END
|
|
|
|
for align in [:Left, :Right, :Center]
|
|
infile = StringIO.new(textinfile)
|
|
puts "\n# %s Column-aligned output:" % align
|
|
puts aligner(infile, align)
|
|
end
|