Why doesn't input code return 'plants' as in 'Getting Started with Beautiful Soup' text (on page 30) ?

[Simon Evans]

Dear Peter Otten, thank you for your reply that I have not gone very far into the detail of which, as it seems Python console cannot recognise the name 'f' as given it, re output below :


Python 2.7.6 (default, Nov 10 2013, 19:24:18) [MSC v.1500 32 bit (Intel)] on win
32
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>>> from bs4 import BeautifulSoup
>>> with open("C:\Beautiful Soup\ecologicalpyramid.html","r")as f:
>>> soup = BeautifulSoup(f, "lxml")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'f' is not defined
>>>