get dictionary value by key python code example

Example 1: 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 2: get function in dictionary

#The get() method in  dictionary returns:
#the value for the specified key if key is in dictionary.
#None if the key is not found and value is not specified.
#value if the key is not found and value is specified.
# value is provided
print('Salary: ', person.get('salary', 0.0))

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() python

# The get() method on dicts
# and its "default" argument

name_for_userid = {
    382: "Alice",
    590: "Bob",
    951: "Dilbert",
}

def greeting(userid):
    return "Hi %s!" % name_for_userid.get(userid, "there")

>>> greeting(382)
"Hi Alice!"

>>> greeting(333333)
"Hi there!"

'''When "get()" is called it checks if the given key exists in the dict.

If it does exist, the value for that key is returned.

If it does not exist then the value of the default argument is returned instead.
'''
# transferred by @ebdeuslave
# From Dan Bader - realpython.com

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