Extract text from PDF documents

To extract a text from PDF documents GetText and GetText(pageIndex) method is used. These methods allow to extract a text from the entire document or a text from the selected page.

Here are the steps to extract a text from PDF document:

Instantiate Parser object for the initial document;
Call GetText method and obtain TextReader object;
Read a text from reader.

GetText method returns null value if text extraction isn’t supported for the document. For example, text extraction isn’t supported for Zip archive. Therefore, for Zip archive GetText method returns null. For empty PDF document GetText method returns an empty TextReader object (reader.ReadToEnd method returns an empty string).

The following example demonstrates how to extract a text from PDF document:

// Create an instance of Parser class
using(Parser parser = new Parser(filePath))
{
    // Extract a text into the reader
    using(TextReader reader = parser.GetText())
    {
        // Print a text from the document
        Console.WriteLine(reader.ReadToEnd());
    }
}

Here are the steps to extract a text from the page of PDF document:

Instantiate Parser object for the initial document;
Call GetDocumentInfo method and obtain IDocumentInfo object with page count;
Call GetText(pageIndex) method with the page index and obtain TextReader object;
Read a text from reader.

The following example demonstrates how to extract a text from the page of PDF document:

// Create an instance of Parser class
using(Parser parser = new Parser(filePath))
{
    // Get the document info
    IDocumentInfo documentInfo = parser.GetDocumentInfo();
   
    // Iterate over pages
    for(int p = 0; p < documentInfo.PageCount; p++)
    {
        // Print a page number 
        Console.WriteLine(string.Format("Page {0}/{1}", p + 1, documentInfo.PageCount));
   
        // Extract a text into the reader
        using(TextReader reader = parser.GetText(p))
        {
            // Print a text from the document
            Console.WriteLine(reader.ReadToEnd());
        }
    }
}

Raw mode allows to increase the speed of text extraction due to poor formatting accuracy. GetText(TextOptions) and GetText(pageIndex, TextOptions) methods are used to extract a text in raw mode.

Some documents may have different page numbers in raw and accurate modes. Use DocumentInfo.RawPageCount instead of IDocumentInfo.PageCount in raw mode.

Here are the steps to extract a raw text from the page of PDF document:

Instantiate Parser object for the initial document;
Instantiate TextOptions object with true parameter;
Call GetDocumentInfo;
Use RawPageCount instead of PageCount to avoid extra calculations;
Call GetText(pageIndex, TextOptions) method with the sheet index and obtain TextReader object;
Read a text from reader.

The following example demonstrates how to extract a raw text from the page of PDF document:

// Create an instance of Parser class
using (Parser parser = new Parser(filePath))
{
    // Get the document info
    IDocumentInfo documentInfo = parser.GetDocumentInfo();
    // Check if the document has pages
    if (documentInfo == null || documentInfo.RawPageCount == 0)
    {
        Console.WriteLine("Document hasn't pages.");
        return;
    }
    // Iterate over pages
    for (int p = 0; p < documentInfo.RawPageCount; p++)
    {
        // Print a pagenumber 
        Console.WriteLine(string.Format("Slide {0}/{1}", p + 1, documentInfo.RawPageCount));
        // Extract a text into the reader
        using (TextReader reader = parser.GetText(p, new TextOptions(true)))
        {
            // Print a text from the document page
            Console.WriteLine(reader.ReadToEnd());
        }
    }
}

More resources

GitHub examples

You may easily run the code above and see the feature in action in our GitHub examples:

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