Introducing three methods of accessing dictionaries

Definition dictionary dic = {'a':"hello",'b':"how",'c':"you"}

Method 1:

for key in dic:
　　print key,dic[key]
　　print key + str(dic[key])

Result:

　　a hello
　　ahello
　　c you
　　cyou
　　b how
　　bhow

Details:

print key,dic[key], followed by a comma, automatically generates a space

print key + str(dic[key]), connection Two strings , using the plus sign, output directly without commas in between

Method 2:

for (k,v) in dic.items():
　　print "dic[%s]="%k,v

Result:

　dic[a]= hello
　　dic[c]= you
　　dic[b]= how

Method Three:

for k,v in dic.iteritems():
　　print "dic[%s]="%k,v

Result:

　　dic[a]= hello
　　dic[c]= you
　　dic[b]= how

Contrast:

items() returns a list object, while iteritems() returns an iterator object . For example:

print dic.items()        #[('a', 'hello'), ('c', 'you'), ('b', 'how')]
print dic.iteritems()   #<dictionary-itemiterator object at 0x020E9A50>

Digging deeper: iteritor means iterator, one data item at a time, until it lasts

 for i in dic.iteritems():
　　 print i

Result:

('a', 'hello')
('c', 'you')
('b', 'how')

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