Dictionary in Python

Dictionary  in Python like list is a collection of objects.Unlike lists ,items in dictionary are accessed by key.Similar to lists ,items can be added or removed from dictionary.While the items in a list are sorted in a specific order ,the items in a dictionary are not sorted.The size of dictionary is not fixed ,items can be added or removed from the dictionary.

Creating a dictionary

To create a dictionary you specify key,value pairs.The keys and values are separated by colon.

Dictionary is declared using the parenthesis as:

dict = {'item1': 1, 'item2': 2}

In the above dictionary there are two elements.The key of first element is ‘item1’ and key of the second element is ‘item2’ .

once dictionary is declared you can modify the dictionary by using the key as:

dict['item2']="two"

You can get the length of the dictionary by using the len() function as:

dict.len(dict)

The items in the dictionary can be retreived by using the items method as:

dict.items()

Removing item from a dictionary

You can delete item from a dictionary using the del keyword as:

del sampleDict['2']

looping through the items in the dictionary

for x in sampleDict:
print('x=%s'%(sampleDict[x]))

ashish