maps hashable values to arbitrary objects

mutable

More than one entry per key not allowed

Keys must be immutable, like strings, numbers, or tuples

# Create a dict
dict = {}
 
# Create a dict with initial values
dict = {'Name': 'Zara', 'Age': 7, 'Class': 'First'}
		

# Change the value of a key word
dict['Name'] = 'Lin'
 
# Add a new key and value
dict['Major'] = 'CS'
		

# Delete an element of the dict
del dict['Name']
 
# Remove all elements of the dict
dict.clear()
 
# Remove the whole dict
del dict
		

# cmp, compare two dicts
dict1 = {'Name':'Lin', 'Age':37}
dict2 = {'Name':'Lin', 'Age':37}
print cmp(dict1, dict2)
 
#len, get the number of items in dict
print len(dict1)
 
#str, convert a dict to a string
print str(dict1)
 
#type, check type
print type(dict1)
 
#id, get the memory id of the dict
print id(dict1)
		

#!/usr/bin/python
 
d = {}; #create a dict
 
d['Name'] = 'Lin';
d['Age'] = 38;
 
#has_key()
if d.has_key('Name'):
    print 'Has key \'Name\'';
if 'Name' in d:
    print 'Has key \'Name\'';
 
#get, returns a value for the given key; if key is not available then returns default value
print d.get('Name');
print d.get('Temp', 'Unknown');
#print d['Temp']; # throw KeyError
 
#items, return a list of tuples of (key, value) pairs
items = d.items();
print items
 
#keys, return a list of keys
keys = d.keys();
print keys;
 
#values, return a list of values
values = d.values();
print values
 
#setdefault, get the value of key; if key is not available then return default value
print d.setdefault('Age', None); #38
print d.setdefault('Sex', None); #None
 
#update, add a dict to another dict
d2 = {'Sex': 'M', 'State': 'VA'};
d.update(d2); #{'Name':'Lin', 'Age':38, 'Sex':'M', 'State':'VA'}
print d
 
#remove and retun an arbitrary key-value pair
print d.popitem();
			

#!/usr/bin/python
 
d = {'Name': 'Lin', 'Age': 38, 'Sex': 'M', 'State': 'VA'};
 
#iterkeys
i = d.iterkeys();
 
while 1:
    try:
        e = i.next();
    except StopIteration:
        break;
    else:
        print e,
print
 
#itervalues
iv = d.itervalues();
for v in iv:
    print v,
print
 
#iteritems
it = d.iteritems();
for t in it:
    print t;
			

Python How to Program

STL