python dictionary get value by key code example

Example 1: python dictionary get default

dictionary = {"message": "Hello, World!"}

data = dictionary.get("message", "")

print(data)  # Hello, World!

Example 2: python get dictionary keys

# To get all the keys of a dictionary use 'keys()'
newdict = {1:0, 2:0, 3:0}
newdict.keys()
# Output:
# dict_keys([1, 2, 3])

Example 3: python get value from dictionary

dict = {'color': 'blue', 'shape': 'square', 'perimeter':20}
dict.get('shape') #returns square

#You can also set a return value in case key doesn't exist (default is None)
dict.get('volume', 'The key was not found') #returns 'The key was not found'

Example 4: get a value from a dictionary python

#!/usr/bin/python

dict = {'Name': 'Zabra', 'Age': 7}
print "Value : %s" %  dict.get('Age')
print "Value : %s" %  dict.get('Education', "Never")

Example 5: python dictionary access value by key

# Create a list of dictionary
datadict = [{'Name': 'John', 'Age': 38, 'City': 'Boston'},
 {'Name': 'Sara', 'Age': 47, 'City': 'Charlotte'},
 {'Name': 'Peter', 'Age': 63, 'City': 'London'},
 {'Name': 'Cecilia', 'Age': 28, 'City': 'Memphis'}]

# Build a function to access to list of dictionary
def getDictVal(listofdic, name, retrieve):
    for item in listofdic:
        if item.get('Name')==name:
            return item.get(retrieve)
          
 # Use the 'getDictVal' to read the data item
getDictVal(datadict, 'Sara', 'City') # Return 'Charlotte'

# -------------------
# to convert a dataframe to data dictionary
df = pd.DataFrame({'Name': ['John', 'Sara','Peter','Cecilia'],
                   'Age': [38, 47,63,28],
                  'City':['Boston', 'Charlotte','London','Memphis']})

datadict = df.to_dict('records')

Example 6: how to get value from key dict in python

# Get a value from a dictionary in python from a key

# Create dictionary
dictionary = {1:"Bob", 2:"Alice", 3:"Jack"}

# Retrieve value from key 2
entry = dictionary[2]

# >>> entry
# Alice