Python Dictionary - GeeksforGeeks

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.

# Create a new dictionary  
d = dict() # or d = {} 
  
# Add a key - value pairs to dictionary 
d['xyz'] = 123
d['abc'] = 345
  
# print the whole dictionary 
print(d) 
  
# print only the keys 
print(d.keys()) 
  
# print only values 
print(d.values()) 
  
# iterate over dictionary  
for i in d : 
    print("%s  %d" %(i, d[i])) 
  
# another method of iteration 
for index, value in enumerate(d): 
    print (index, value , d[value]) 
  
# check if key exist 
print('xyz' in d) 
  
# delete the key-value pair 
del d['xyz'] 
  
# check again  
print("xyz" in d) 

Output:

{'xyz': 123, 'abc': 345}
['xyz', 'abc']
[123, 345]
xyz 123
abc 345
0 xyz 123
1 abc 345
True
False

Dictionary Programs, Built-in Functions

Built-in Functions

Dict.cmp(): Compares elements of both dict.
Dict.len(): Gives the total length of the dictionary.
Dict.str(): Produces a printable string representation of a dictionary.
Dict.type(): Returns the type of the passed variable.
Dict.clear(): Removes all elements of dictionary dict
Dict.copy(): Returns a shallow copy of dictionary dict
Dict.fromkeys(): Create a new dictionary with keys from seq and values set to value.
Dict.get(): For key, returns value or default if key not in dictionary
Dict.has_key(): Returns true if key in dictionary dict, false otherwise
Dict.items(): Returns a list of dict’s (key, value) tuple pairs
Dict.keys(): Returns list of dictionary dict’s keys
Dict.setdefault(): Set dict[key]=default if key is not already in dict
Dict.update(): Adds dictionary dict2’s key-values pairs to dict
Dict.values(): Returns list of dictionary dict’s values

Dictionary Programs

Useful Links

My Personal Notes

ayushmaan bansal

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