PYTHON

create dictionary python from two lists

>>> keys = ['a', 'b', 'c']
>>> values = [1, 2, 3]
>>> dictionary = dict(zip(keys, values))
>>> print(dictionary)
{'a': 1, 'b': 2, 'c': 3}

convert 2 lists to a dictionary in python

""" How to convert 2 lists into a dictionary in python """
# list used for keys in dictionary
students = ["Angela", "James", "Lily"]

# list of values
scores = [56, 76, 98]

# convert lists to dictionary
student_scores = dict(zip(students, scores))

# print the dictionary
print(student_scores)

""" result should be
student_scores: -{
        Angela: 56,
        James: 76,
        Lily: 98
    },
"""

python merge two dictionaries

d1 = {'name': 'Alex', 'age': 25}
d2 = {'name': 'Alex', 'city': 'New York'}
merged_dict = {**d1, **d2}
print(merged_dict) # {'name': 'Alex', 'age': 25, 'city': 'New York'}

python merge dictionaries

# Python >= 3.5:
def merge_dictionaries(a, b):
   return {**a, **b}
  
# else:
def merge_dictionaries(a, b):
    c = a.copy()   # make a copy of a 
    c.update(b)    # modify keys and values of a with the b ones
    return c

a = { 'x': 1, 'y': 2}
b = { 'y': 3, 'z': 4}
print(merge_dictionaries(a, b)) 		# {'y': 3, 'x': 1, 'z': 4}

merge two dict python 3

z = {**x, **y}

Merge dictionaries in python

dict_1 = {'John': 15, 'Rick': 10, 'Misa' : 12 }
dict_2 = {'Bonnie': 18,'Rick': 20,'Matt' : 16 }
dict_1.update(dict_2)
print('Updated dictionary:')
print(dict_1)

python Merge Two Dictionaries

dict_1 = {1: 'a', 2: 'b'}
dict_2 = {2: 'c', 4: 'd'}

dict_3 = dict_2.copy()
dict_3.update(dict_1)

print(dict_3)

python merge dictionaries

dict1 = {'color': 'blue', 'shape': 'square'}
dict2 = {'color': 'red', 'edges': 4}

dict1.update(dict2) #if a key exists in both, it takes the value of the second dict
# dict1 = {'color': 'red', 'shape': 'square', 'edges': 4}
# dict2 is left unchanged

how to merge two dictionaries

>>> dict_a = {'a': 1, 'b': 2}
>>> dict_b = {'b': 3, 'c': 4}
>>> dict_c = {**dict_a, **dict_b}
>>> dict_c
# {'a': 1, 'b': 3, 'c': 4}

Python merge two dictionaries

# Python 3.9
z = x | y

# Python 3.5
z = {**x, **y}

# Python <= 3.4
def merge_two_dicts(x, y):
    z = x.copy()   # start with keys and values of x
    z.update(y)    # modifies z with keys and values of y
    return z

z = merge_two_dicts(x, y)

python merge nested dictionaries

# Example usage:
# Say you have the following dictionaries and want to merge dict_b into dict_a
dict_a = {"ABC": {"DE": {"F": "G"}}}
dict_b = {"ABC": {"DE": {"H": "I"}, "JKL": "M"}} 

def merge_nested_dictionaries(dict_a, dict_b, path=None):
    """
    recursive function for merging dict_b into dict_a
    """
    if path is None:
        path = []
    for key in dict_b:
        if key in dict_a:
            if isinstance(dict_a[key], dict) and isinstance(dict_b[key], dict):
                merge_nested_dictionaries(dict_a[key], dict_b[key], path + [str(key)])
            # if the b dictionary matches the a dictionary from here on, skip adding it
            elif dict_a[key] == dict_b[key]:
                pass
            # if the same series of keys lead to different terminal values in
            # each dictionary, the dictionaries can't be merged unambiguously
            else:
                raise Exception('Conflict at %s' % '.'.join(path + [str(key)]))
        # if the key isn't in a, add the rest of the b dictionary to a at this point
        else:
            dict_a[key] = dict_b[key]
    return dict_a

# running:
merge_nested_dictionaries(dict_a, dict_b)
# returns:
{'ABC': {'DE': {'F': 'G', 'H': 'I'}, 'JKL': 'M'}}

Convert two lists into a dictionary in Python

>>> students = ["Cody", "Ashley", "Kerry"]
>>> grades = [93.5, 95.4, 82.8]
>>> {s: g for s, g in zip(students, grades)}
{'Cody': 93.5, 'Ashley': 95.4, 'Kerry': 82.8}

merge dicts python

z = x | y          # NOTE: 3.9+ ONLY
z = {**x, **y}		# NOTE: 3.5+ ONLY

create dict from two lists

keys = ['a', 'b', 'c']
values = [1, 2, 3]
dictionary = dict(zip(keys, values))

merge two dictionaries

# merge two dictionaries
x = {'a': 1,'b':2}
y = {'d':3,'c':5}
z = {**x, **y}
print(z)					# {'a': 1, 'b': 2, 'd': 3, 'c': 5}

merge a list of dictionaries python

>>> from collections import ChainMap
>>> a = [{'a':1},{'b':2},{'c':1},{'d':2}]
>>> dict(ChainMap(*a))
{'b': 2, 'c': 1, 'a': 1, 'd': 2}

how to merge two dictionaries with same keys in python

from collections import defaultdict

d1 = {1: 2, 3: 4}
d2 = {1: 6, 3: 7}

dd = defaultdict(list)

for d in (d1, d2): # you can list as many input dicts as you want here
    for key, value in d.items():
        dd[key].append(value)

print(dd)

merged all dictionaries in a list python

>>> result = {}
>>> for d in L:
...    result.update(d)
... 
>>> result
{'a':1,'c':1,'b':2,'d':2}

python merge list of dict into single dict

l = [{'a': 0}, {'b': 1}, {'c': 2}, {'d': 3}, {'e': 4, 'a': 4}]
d = {k: v for x in l for k, v in x.items()}
print(d)
# {'a': 4, 'b': 1, 'c': 2, 'd': 3, 'e': 4}

python merge dict

# Python 3.9+ is required
mergedDict = dict1 | dict2

python merge dictionaries

def merge_dicts(dict1, dict2):
        """Here's an example of a for-loop being used abusively."""
        return {**dict2, **{k: (v if not (k in dict2) else (v + dict2.get(k)) if isinstance(v, list) else merge_dicts(v, dict2.get(k))) if isinstance(v, dict) else v for k, v in dict1.items()}}

Converting Two Lists Into a Dictionary

column_names = ['id', 'color', 'style']
column_values = [1, 'red', 'bold']

# Convert two lists into a dictionary with zip and the dict constructor
name_to_value_dict = dict(zip(column_names, column_values))

# Convert two lists into a dictionary with a dictionary comprehension
name_to_value_dict = {key:value for key, value in zip(column_names, column_values)}

# Convert two lists into a dictionary with a loop
name_value_tuples = zip(column_names, column_values) 
name_to_value_dict = {} 
for key, value in name_value_tuples: 
  if key in name_to_value_dict: 
    pass # Insert logic for handling duplicate keys 
  else: 
    name_to_value_dict[key] = value

merge two list of dictionaries python with string

import pandas as pd

l1 = [{'id': 9, 'av': 4}, {'id': 10, 'av': 0}, {'id': 8, 'av': 0}]
l2 = [{'id': 9, 'nv': 45}, {'id': 10, 'nv': 0}, {'id': 8, 'nv': 30}]

df1 = pd.DataFrame(l1).set_index('id')
df2 = pd.DataFrame(l2).set_index('id')
df = df1.merge(df2, left_index=True, right_index=True)
df.T.to_dict()
# {9: {'av': 4, 'nv': 45}, 10: {'av': 0, 'nv': 0}, 8: {'av': 0, 'nv': 30}}

merge two dict python

For dictionaries x and y, their shallowly-merged dictionary z takes values from y, replacing those from x.

In Python 3.9.0 or greater (released 17 October 2020, PEP-584, discussed here):

z = x | y
In Python 3.5 or greater:

z = {**x, **y}
In Python 2, (or 3.4 or lower) write a function:

def merge_two_dicts(x, y):
    z = x.copy()   # start with keys and values of x
    z.update(y)    # modifies z with keys and values of y
    return z
and now:

z = merge_two_dicts(x, y)

make dict from 2 lists

keys = ['a', 'b', 'c']
values = [1, 2, 3]
dictionary = dict(zip(keys, values))
print(dictionary) # {'a': 1, 'b': 2, 'c': 3}

create a dict from two lists

zip_iterator = zip(keys_list, values_list)

python Merge Two Dictionaries

dict_1 = {1: 'a', 2: 'b'}
dict_2 = {2: 'c', 4: 'd'}

print(dict_1 | dict_2)

python Merge Two Dictionaries

dict_1 = {1: 'a', 2: 'b'}
dict_2 = {2: 'c', 4: 'd'}

print({**dict_1, **dict_2})

convert 2 lists into dictionary

# convert 2 list into dictionary
a = ['gsw','lakers','clippers']
b = [1,2,3]
my_dict = dict(zip(a,b))
print(my_dict)					# {'gsw': 1, 'lakers': 2, 'clippers': 3}

python two list into dictinaray

index = [1, 2, 3]
languages = ['python', 'c', 'c++']

dictionary = dict(zip(index, languages))
print(dictionary)

merge lists dictionary

# (*) unpacking operator
    # for positional vs keyword argument, see "03 functions"
    # for packing, see "03 functions"       
# * can unpack iterables eg tuple, list, strings etc to its elements. 
# ** can only unpack dictionary

# convert range til list
l1 = [range(5)]     
print(l1)
#[range(0, 5)]

l = [*range(5)]     # * unpacking operator
print(l)
#[0, 1, 2, 3, 4]


# unpacking a collection
my_tuple = (1, 2, 3, 4, 5, 6, 7)
i1, *i2, i3, i4 = my_tuple      # the middle part of the tuple gets unpacked into a list in i2
print(i1)
print(i2)
print(i3)
print(i4)
# 1
# [2, 3, 4, 5]
# 6
# 7


# merge containers
my_tuple = (1, 2, 3)
my_list = [4, 5, 6]
merged_list = [*my_tuple, *my_list]
print(merged_list)
# [1, 2, 3, 4, 5, 6]

dict_a = {'a':1, 'b':2}
dict_b = {'c':3, 'd':4}
merged_dict = {**dict_a, **dict_b}
print(merged_dict)
# {'a': 1, 'b': 2, 'c': 3, 'd': 4}


# unpacking arguments passed to function calls
# Ex 1: unpack collections into func arguments
def foo(a, b, *args, **kwargs):
    print(a, end = ' ')
    for arg in args:    #args is unpacked into an iterable object
        print(arg, end = ' ')
    for key in kwargs:
        print(key, kwargs[key], end = ' ')

foo(1, 2, 3, 4, 5, six=6, seven=7)
# 1 3 4 5 six 6 seven 7 
values = (1, 2, 3, 4, 5)
mydict = {'eight': 8, 'nine': 9}
foo(*values, **mydict)    #NB! * unpacking operator, otherwise passing a tuple + dict
#1 3 4 5 eight 8 nine 9   #NB! ** for dict, otherwise only get keys


# Ex 2: matching parameters with unpacked arguments
def myFun(a, b, c):
    print("a:", a)
    print("b:", b)
    print("c:", c)
     
# keys in dictionary must be the same as names of parameters
kwargs = {"a" : "One", "b" : "Two", "c" : "Three"}  #dictionary
myFun(**kwargs)     # passing a dictionary into myFun() by unpacking it and pass individual key:value pair
# a: One
# b: Two
# c: Three