avoid for loop calling Generator function

Arshpreet Singh arsh840 at gmail.com
Mon Feb 22 10:38:09 EST 2016


On Monday, 22 February 2016 19:05:24 UTC+5:30, Peter Otten  wrote:
> Arshpreet Singh wrote:
> 
> > Hi, I am converting PDF into text file, I am using following code.
> > 
> > from pypdf2 import PdfFileReader
> > 
> > def read_pdf(pdfFileName):
> > 
> >     pdf = PdfFileReader(pdfFileName)
> > 
> >     yield from (pg.extractText() for pg in pdf.pages)
> > 
> > for i in read_pdf('book.pdf'):
> >      print(i)
> > 
> > I want to avoid for loop , I also tried to create another function and
> > call read_pdf() inside that new function using yield from but I think I am
> > missing real picture here
> 
> While it is possible to replace the loop with
> 
> next(filter(print, read_pdf("book.pdf")), None)

Why we are w=using filter here?
 
> or the slightly less convoluted
> 
> sys.stdout.writelines(map("{}\n".format, read_pdf("book.pdf")))

Actually I am using this function in Android App which is being built using Kivy, Where I am returning whole text into a file, So what you think will be more efficient way? 

> the for loop is the obvious and therefore recommended solution. Personally, 
> I would also replace
> 
> >     yield from (pg.extractText() for pg in pdf.pages)
> 
> with the good old
> 
> for pg in pdf.pages:
>     yield pg.extractText()
> 
> and reserve the generator expression for occasions where it has a 
> demonstrable advantage in readability.
But when I am calling pdf_read() from nother function to avoid for loop why it is not working?
say:

def hello()
    yield from read_pdf('book.pdf')

print(hello()) # still returns memory location instead of text. If I am not wrong yield from can be used to avoid for loop? 


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