CODEWITHSUNDEEP
pythonpython-2.7
runcode
runcode

Reputation: 3643

python basic syntax boolean compare

i have a question about the following code

 smaller={}
 for( dest in a[neigbour].keys())

    if(dest in smaller.keys() == False):
        print 'false'
    }

I can't make this code print false.. am I doing something wrong? I wonder if I am doing the correct thing to check the statement dest in smaller.keys() == False

Upvotes: 0

Views: 250

Answers (3)

Jon Clements
Jon Clements

Reputation: 142176

As well as the other answers you've been given, the code could be written as:

for key in a[neighbour].viewkeys() - smaller.viewkeys():
    print key, 'not found'

Which takes advantage of the set like behaviour of .viewkeys to easily create a set of all keys in a[neighbour] not in b, then loops over that.

Upvotes: 1

Yuushi
Yuushi

Reputation: 26050

Your Python syntax is quite confused. For one, you need a : after your for statement, and it's generally not idiomatic to use braces around a for loop in Python. Also, instead of comparing to False with ==, generally we use not:

smaller = {}
for dest in a[neighbour].keys():
    if dest not in smaller.keys():
        print('false')

Upvotes: 4

mathematical.coffee
mathematical.coffee

Reputation: 56915

The oppisite of dest in smaller.keys() is dest not in smaller.keys(). No need to compare to False or True:

if (dest not in smaller.keys()):

Documentation for in and not in: http://docs.python.org/library/stdtypes.html#sequence-types-str-unicode-list-tuple-bytearray-buffer-xrange

Upvotes: 4

Related Questions