DICTIONARY QUESTIONS

Question 1

Dictionary?

Answer 1

In python, dictionary is similar to hash or maps in other languages. It consists of key value pairs. The value can be accessed by unique key in the dictionary.

Question 2

Create a new dictionary

Answer 2

Create a new dictionary
d = dict()
# or you can do
d = {}

Question 3

Add a key - value pairs to dictionary

Answer 3

Add a key - value pairs to dictionary
d[‘xyz’] = 123
d[‘abc’] = 345
returns {‘xyz’: 123, ‘abc’: 345}

Question 4

print the whole dictionary

Answer 4

print the whole dictionary
print(d)

Question 5

print only the keys

Answer 5

A
# print only the keys
print(d.keys())
returns [‘key1’, ‘key2’,…]
#notice the parens around the keys

Question 6

print only values

Answer 6

print only values
print(d.values())
returns [value1, value2]
#notice the lack of parens around the values

Question 7

iterate over dictionary

Answer 7

iterate over dictionary
for i in d :
print(“%s %d” %( i, d[i] ) )

Question 8

another way of iteration over a dictionary

Answer 8

another method of iteration
for index, value in enumerate(d):
print (index, value , d[value])

Question 9

check if key exist

Answer 9

check if key exist
print(‘xyz’ in d)

Question 10

delete the key-value pair

Answer 10

delete the key-value pair
del d[‘xyz’]

Question 11

Dict.cmp()

Answer 11

Dict.cmp(): Compares elements of both dict.

Question 12

Dict.len()

Answer 12

Dict.len(): Gives the total length of the dictionary.

Question 13

Dict.str()

Answer 13

Dict.str(): Produces a printable string representation of a dictionary.

Question 14

Dict.type()

Answer 14

Dict.type(): Returns the type of the passed variable

Question 15

Dict.clear()

Answer 15

Dict.clear(): Removes all elements of dictionary dict

Question 16

Dict.copy()

Answer 16

Dict.copy(): Returns a shallow copy of dictionary dict