Ruby Requires Chilkat v11.7.0+

Get Every Occurrence of a Label in a PDF

See more PDF Text Extraction Examples

Demonstrates the "labelOccurrence" option. When the same label appears more than once (for example "Total:" on each of several receipts), "first" (the default) uses the first occurrence, "all" returns every occurrence with its page, and a number selects one occurrence. Ruby

require 'chilkat'

success = false

#  This example requires the Chilkat API to have been previously unlocked.
#  See Global Unlock Sample for sample code.

#  The PDF used in this example (three receipts, one per page) is available at three_receipts.pdf

pdf = Chilkat::CkPdf.new()
success = pdf.LoadFile("qa_data/pdf/three_receipts.pdf")
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

json = Chilkat::CkJsonObject.new()
jsonOut = Chilkat::CkJsonObject.new()

#  Each of the three pages is a receipt with a "Total:" line.
json.UpdateString("label","Total")
json.UpdateString("labelValue","right")

#  By default only the first occurrence (in reading order) is used.
success = pdf.ExtractText("text",json,jsonOut)
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

print "First total: " + jsonOut.stringOf("text") + "\n";

#  labelOccurrence "all" returns every occurrence.  The "text" member holds the values joined
#  by line breaks, and labelMatches has one entry per occurrence with its page.
json.UpdateString("labelOccurrence","all")
success = pdf.ExtractText("text",json,jsonOut)
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

i = 0
count_i = jsonOut.SizeOfArray("labelMatches")
while i < count_i
    jsonOut.put_I(i)
    print "Page " + jsonOut.IntOf("labelMatches[i].page").to_s() + " total: " + jsonOut.stringOf("labelMatches[i].text") + "\n";
    i = i + 1
end

#  A number selects one occurrence: 2 is the second.
json.UpdateInt("labelOccurrence",2)
success = pdf.ExtractText("text",json,jsonOut)
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

print "Second total: " + jsonOut.stringOf("text") + "\n";

#  The occurrences are counted over the selected pages, so combining "pages" with the label
#  is another way to pick one receipt:
json.UpdateString("labelOccurrence","first")
json.UpdateString("pages","3")
json.UpdateString("label","Receipt No.")
success = pdf.ExtractText("text",json,jsonOut)
if (success == false)
    print pdf.lastErrorText() + "\n";
    exit
end

print "Receipt number on page 3: " + jsonOut.stringOf("text") + "\n";

#  Sample output:

#  First total: $19.86
#  Page 1 total: $19.86
#  Page 2 total: $17.34
#  Page 3 total: $23.62
#  Second total: $17.34
#  Receipt number on page 3: 1003