14

Why won't this work : 

with open('file.pdf', 'w') as outfile:
    outfile.write("Hello")

The code works fine, but the .pdf file cannot be opened. What's the difference between a normal text file and pdf? What to do if I want to create and write to a pdf file in python?

gsamaras
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    Appreciate your ambition, Unfortunately writing to PDFs requires additional libraries like PyPDF or Reportlabs. Search for those. – nehem Aug 30 '17 at 06:53
  • There are many differences between text files and pdfs. Open a pdf file with a text editor and you will see. – philippd Aug 30 '17 at 06:57
  • @itsneo PyPDF seems outdated. I posted an answer with an update. What do you think? – gsamaras Aug 30 '17 at 07:01
  • Reasonable explanation of a [minimal PDF file here]( https://brendanzagaeski.appspot.com/0004.html). Illustrates why the sample code provided will not work as-is. – Vanquished Wombat Aug 30 '17 at 08:50

3 Answers3

18

you could install the fpdf library and then:

from fpdf import FPDF

pdf = FPDF()
pdf.add_page()
pdf.set_xy(0, 0)
pdf.set_font('arial', 'B', 13.0)
pdf.cell(ln=0, h=5.0, align='L', w=0, txt="Hello", border=0)
pdf.output('test.pdf', 'F')
Rasmus Lyngdal-Christensen
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7

What's the difference between a normal text file and pdf?

A PDF file has a specific format. You can read more here. A text is a much simpler file, thus when you attempt to open a file that you think it's a PDF, but doesn't have this format, the file cannot be opened.

What to do if I want to create and write to a pdf file in python?

You need to use a module, like PyPDF2, Reportlab or FPDF. Moreover read Python PDF library.

gsamaras
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2

Every type of file has its own internal format - a set of rules about what has to go where to define the information it is meant to represent. Usually the file extension ('.pdf' in this case) is set to tell you what internal format a file uses, but there's no absolute guarantee of that.

If you write a string to a file with Python, the file will have exactly what you put in it, in this case just the five ASCII characters H, e, l, l and o. That would correspond to the normal format for a text file. So in this case, you have created a text file but put a '.pdf' extension on it. Its internal format is still a text file, and if you rename it to 'file.txt', you'll find you can open it just fine (with a text editor).

If you want to create a true PDF file (something with the correct internal format for a PDF), you would need to use a specialized package that can write that type of file. @gsamaras and @rasmus-lyngdal-christensen gave some good suggestions (Reportlab, PyPDF2 and fpdf).

Matthias Fripp
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