Common Dictionary Operations in Python

Dictionary

A dictionary constant consists of a series of key-value pairs enclosed by curly
braces { }

With dictionaries you can store things so that you quickly can find them again

Dictionary Operations

Below is a list of common dictionary operations:

create an empty dictionary
x = {}

create a three items dictionary
x = {"one":1, "two":2, "three":3}

access an element
x['two']

get a list of all the keys
x.keys()

get a list of all the values
x.values()

add an entry
x["four"]=4

change an entry
x["one"] = "uno"

delete an entry
del x["four"]

make a copy
y = x.copy()

remove all items
x.clear()

number of items
z = len(x)

test if has key
z = x.has_key("one")

looping over keys
for item in x.keys(): print item

looping over values
for item in x.values(): print item

using the if statement to get the values
if "one" in x:
    print x['one']

if "two" not in x:
    print "Two not found"

if "three" in x:
    del x['three']