Answers for "python dict key value"

python dictionary

#Creating dictionaries
dict1 = {'color': 'blue', 'shape': 'square', 'volume':40}
dict2 = {'color': 'red', 'edges': 4, 'perimeter':15}

#Creating new pairs and updating old ones
dict1['area'] = 25 #{'color': 'blue', 'shape': 'square', 'volume': 40, 'area': 25}
dict2['perimeter'] = 20 #{'color': 'red', 'edges': 4, 'perimeter': 20}

#Accessing values through keys
print(dict1['shape'])

#You can also use get, which doesn't cause an exception when the key is not found
dict1.get('false_key') #returns None
dict1.get('false_key', "key not found") #returns the custom message that you wrote 

#Deleting pairs
dict1.pop('volume')

#Merging two dictionaries
dict1.update(dict2) #if a key exists in both, it takes the value of the second dict
dict1 #{'color': 'red', 'shape': 'square', 'area': 25, 'edges': 4, 'perimeter': 20}

#Getting only the values, keys or both (can be used in loops)
dict1.values() #dict_values(['red', 'square', 25, 4, 20])
dict1.keys() #dict_keys(['color', 'shape', 'area', 'edges', 'perimeter'])
dict1.items() 
#dict_items([('color', 'red'), ('shape', 'square'), ('area', 25), ('edges', 4), ('perimeter', 20)])

for key value in dict python

a_dict = {"color": "blue", "fruit": "apple", "pet": "dog"}
for key in a_dict:
  print(key, '->', a_dict[key])

# Output:
# color -> blue
# fruit -> apple
# pet -> dog

dictionary in python

#A dictionary has key-value pairs. Here 1,2,3 are the keys and Item1,Item2,Item3 
#are their values respectively. 
dictionaryName = { 1: "Item1", 2: "Item2", 3: "Item3"}

#retrieving value of a particular key
dictionaryName[1]

#retrieving all the keys in a dictionary
dictionaryName.keys()

#retrieving all the values in a dictionary
dictionaryName.values()