Dictionary Built In Methods

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Built in Methods for DICTIONARY Class to perform certain operations

  • clear() : remove all items from dictionary


 #program 

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d1.clear()
 print("d1 : ", d1)


 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d1 :  {}


  • copy() : return a shallow copy of dictionary

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d2 = d1.copy()
 print("d2 : ", d2)


 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d2 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}


  • get() : return value of key passed, return NONE if KEY not present

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 value_1 = d1.get(1)            #Key 1 is present
 print("value_1 : ", value_1)

 value_2 = d1.get(3)            #key 3 is not present
 print("value_2 : ", value_2)

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 value_1 :  {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}
 value_2 :  None


  • fromkeys() : return a dictionary with specified Key and Value as NONE

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d2 = d1.fromkeys(d1)
 print("d2 : ", d2)

 d3 = d1.fromkeys(d1[1])
 print("d3 : ", d3)

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d2 :  {1: None, 2: None}
 d3 :  {'Name': None, 'Age': None, 'Marks': None}


  • items() : return a dict_items as a  List of,  Tuple of each key and value 

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d2 = d1.items()
 print("d2 : ", d2)
 print("type(d2) : ", type(d2))

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d2 :  dict_items([(1, {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}), (2, {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72})])
 type(d2) :  <class 'dict_items'>


  • keys() : return a dict_items as a List of Dictionary Key(s)

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d2 = d1.keys()
 print("d2 : ", d2)
 print("type(d2) : ", type(d2))

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d2 :  dict_keys([1, 2])
 type(d2) :  <class 'dict_keys'>



 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d2 = d1[1].keys()
 print("d2 : ", d2)
 print("type(d2) : ", type(d2))

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d2 :  dict_keys(['Name', 'Age', 'Marks'])       # keys of d1[1]
 type(d2) :  <class 'dict_keys'>


  • values() : return a List of Dictionary Value(s)

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d2 = d1.values()
 print("d2 : ", d2)
 print("type(d2) : ", type(d2))

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d2 :  dict_values([{'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}])
 type(d2) :  <class 'dict_values'>



 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d2 = d1[1].values()
 print("d2 : ", d2)
 print("type(d2) : ", type(d2))

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d2 :  dict_values(['Techno Xpresss', 28, 80.72])   # values in d1[1]
 type(d2) :  <class 'dict_values'>


  • pop() : remove the value of Key, return Key_Error if Key not present

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d1.pop(1)           # trying to remove Values for Key 1
 print("d1 : ", d1)

 d1.pop(1)           # trying to remove Values for Key 1 again (Key 1 not exist)
 print("d1 : ", d1)

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d1 :  {2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 Traceback (most recent call last):
   File "C:/Self_Practice_Er_M_S_Dandyan/Python/Pycharm/xml/main.py", line 9, in <module>
     d1.pop(1)           # trying to remove Values for Key 1 again (Key 1 not exist)
 KeyError: 1


  • popitem() : remove last inserted Item in Dictionary, return Key_Error if Dictionary is empty

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 d1.popitem()
 print("d1 : ", d1)

 d1.popitem()
 print("d1 : ", d1)

 d1.popitem()           
 print("d1 : ", d1)

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}}
 d1 :  {}
 Traceback (most recent call last):
   File "C:/Self_Practice_Er_M_S_Dandyan/Python/Pycharm/xml/main.py", line 12, in <module>
     d1.popitem()           
 KeyError: 'popitem(): dictionary is empty'


  • setdefault() : return the Value of passed Key, add passed Key with Value as NONE in case Key is not present

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 print("d1 : ", d1)

 value_1 = d1.setdefault(1)      # passing Key that exist
 print("value_1 : ", value_1)
 print("d1 : ", d1)

 value_2 = d1.setdefault(3)      # passing Key that does not exist
 print("value_2 : ", value_2)
 print("d1 : ", d1)


 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 value_1 :  {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}
 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 value_2 :  None
 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}, 3: None}


  • update() : update the Dictionary with specified Item(Key : value)

 #program

 d1 = {1: {"Name": "Techno Xpresss", "Age": 28, "Marks": 80.72}, 2 : {"Name": "M S Dandyan", "Age": 26, "Marks": 90.72}}
 d2 = {3: {"Name": "Mandeep Singh", "Age": 30, "Marks": 85.76}}
 print("d1 : ", d1)
 print("d2 : ", d2)

 d1.update(d2)
 print("d1 : ", d1)

 #output

 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}}
 d2 :  {3: {'Name': 'Mandeep Singh', 'Age': 30, 'Marks': 85.76}}
 d1 :  {1: {'Name': 'Techno Xpresss', 'Age': 28, 'Marks': 80.72}, 2: {'Name': 'M S Dandyan', 'Age': 26, 'Marks': 90.72}, 3: {'Name': 'Mandeep Singh', 'Age': 30, 'Marks': 85.76}}





Location: Bengaluru, Karnataka, India

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