Lua Requires Chilkat v11.7.0+

Replace the Second (or Every) Occurrence of a Label in a PDF

See more PDF Text Replacement Examples

Demonstrates the "occurrence" member of a label entry. By default the first occurrence of a label, in reading order across the selected pages, is replaced; "occurrence" can be a number for the nth, or "all" for every occurrence. The invoice template has "Ref:" twice. Lua

local chilkat = require("chilkat")

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

-- The PDF used in this example is available at invoice_template.pdf

local pdf = chilkat.Pdf.new()
local success = pdf:load_file("qa_data/pdf/invoice_template.pdf")
if not success then
    print(pdf.last_error_text)
    return
end

local json = chilkat.JsonObject.new()
local jsonOut = chilkat.JsonObject.new()

-- This template's {{placeholders}} are not being filled here: "keep" leaves them as they are
-- (the default, "error", would refuse to apply while a placeholder on the page has no value).
json:update_string("unusedPlaceholders", "keep")

-- "Ref:" appears twice on the page (A-1 near the top, A-2 below the totals).
-- The default replaces the first occurrence only.
json:update_string("labels[0].label", "Ref:")
json:update_string("labels[0].value", "B-7")
success = pdf:text_replace("check", json, jsonOut)
if not success then
    print(pdf.last_error_text)
    return
end

print("default: " .. jsonOut:int_of("replacements[0].count") .. " occurrence replaced")

-- The second occurrence only.
json:update_string("labels[0].occurrence", "2")
success = pdf:text_replace("check", json, jsonOut)
if not success then
    print(pdf.last_error_text)
    return
end

print("occurrence 2: " .. jsonOut:int_of("replacements[0].count") .. " occurrence replaced")

-- Every occurrence.
json:update_string("labels[0].occurrence", "all")
success = pdf:text_replace("apply", json, jsonOut)
if not success then
    print(pdf.last_error_text)
    return
end

print("occurrence all: " .. jsonOut:int_of("replacements[0].count") .. " occurrences replaced")

success = pdf:write_file("qa_output/invoice_refs.pdf")
if not success then
    print(pdf.last_error_text)
    return
end

-- Sample output:

-- default: 1 occurrence replaced
-- occurrence 2: 1 occurrence replaced
-- occurrence all: 2 occurrences replaced