Python's String class count() method

Question

I'm reading Mark Pilgrim's Dive into Python 3 and have been staring at this for about an hour now: http://getpython3.com/diveintopython3/strings.html#common-string-methods

>>> s = '''Finished files are the re-
... sult of years of scientif-
... ic study combined with the
... experience of years.'''
>>> s.lower().count('f')
6

In the multi-line string example given, I don't understand why s.lower().count('f') returns 6 instead of 3. I have confirmed that it does return 6. Of course, Pilgrim even points out in his notes that it is in fact 6, but doesn't explain why.

Can someone help me out? Thanks!

Four answers? And 12 total upvotes? (so far). For counting f's? — alan
– alan, Commented May 4, 2012 at 18:35

David Robinson · Accepted Answer · 2012-05-04 18:28:21Z

5

There are 6 f's in that statement. You might be accidentally ignoring the "of"s.

(Indeed, this is a widely circulated brainteaser).

edited May 4, 2012 at 18:28

answered May 4, 2012 at 18:23

David Robinson

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3 Comments

Jeff Erickson Over a year ago

I mean, normally I would admit to just being an idiot, but Pilgrim's comment makes it seem like many would not count the "of"s...

kindall Over a year ago

The "f" in "of" sounds like "v" so if you file words mentally by their sound (as many do), you will miss them.

JoeFish Over a year ago

Don't feel too bad, @JeffErickson, even knowing the answer it took me 3 read-throughs to find the 6th one.

krousey · Accepted Answer · 2012-05-04 18:23:25Z

5

Finished... files... of... of... scientific... of...

answered May 4, 2012 at 18:23

krousey

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Comments

Andrew Clark · Accepted Answer · 2012-05-04 18:32:16Z

4

This might be a helpful visual.

Six f's

answered May 4, 2012 at 18:32

Andrew Clark

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Comments

Jonathan Sternberg · Accepted Answer · 2012-05-04 18:24:57Z

2

Finished files are the result of years of scientific study combined with the experience of years.

The 'lower' makes it so the entire string is lowercase, so make sure to include things like "Finished".

answered May 4, 2012 at 18:24

Jonathan Sternberg

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