Python Web-L06 (Creating dictionary)
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#Creating a dictionary from a list of tuples
# List of tuples
items = [('a', 1), ('b', 2), ('c', 3)]
# Dictionary comprehension
my_dict = {key: value for key, value in items}
print(my_dict)
# Output:{'a': 1, 'b': 2, 'c': 3}
#Creating a dictionary from two lists
#Two lists
keys = ['a', 'b', 'c']
values = [1, 2, 3]
# Dictionary comprehension
my_dict = {k: v for k, v in zip(keys, values)}
print(my_dict)
# Output:{'a': 1, 'b': 2, 'c': 3}
#Creating a dictionary from two lists (lack of 1 item)
#Two lists
keys = ['a', 'b']
values = [1, 2, 3]
# Dictionary comprehension
my_dict = {k: v for k, v in zip(keys, values)}
print(my_dict)
# Output:{'a': 1, 'b': 2, 'c': 3}
# Filtering items in a dictionary
# Original dictionary
original_dict = {'a': 1, 'b': 2, 'c': 3, 'd':4}
# Dictionary comprehension with a condition
filtered_dict = {k: v for k, v in original_dict.items() if v > 2}
filter_list_key = [k for k, v in original_dict.items() if v > 2]
filter_list_value = [v for k, v in original_dict.items() if v > 2]
print(filtered_dict,filter_list_key,filter_list_value)
# Transforming keys and values
# Original dictionary
original_dict = {'a': 1, 'b': 2, 'c': 3}
# Dictionary comprehension with transformation
transformed_dict = {k.upper(): v * 2 for k, v in original_dict.items()}
print(transformed_dict)
# Output:{'A': 2, 'B': 4, 'C': 6}
# Creating a dictionary from a range
# Dictionary comprehension with range; key can include value
my_dict = {x : x**2 for x in range(5)}
print(my_dict)
# Output:{0: 0, 1: 1, 2: 4, 3:9, 4: 16}
# Nested dictionary comprehension
# x : {y: x * y for y in range(1, 4)} -> return value
nested_dict = {x : {y: x * y for y in range(1, 4)} for x in range(1,4)}
print(nested_dict)
# Output:{1: {1: 1, 2: 2, 3: 3}, 2: {1: 2, 2: 4, 3: 6}, 3: {1: 3, 2: 6, 3: 9}}
# Swapping keys and values
# Original dictionary
original_dict = {'a': 1, 'b': 2, 'c': 3}
# Dictionary comprehension to swap keys and values
swapped_dict = {v: k for k, v in original_dict.items()}
print(swapped_dict)
# Output: {1: 'a', 2: 'b', 3: 'c'}
# Creating a dictionary with conditional logic
# List of keys
keys = ['a', 'b', 'c', 'd']
# Dictionary comprehension with conditional logic
my_dict = {k: ('even' if ord(k) % 2 == 0 else 'odd') for k in keys}
print(my_dict)
# Output: {'a': 'odd', 'b': 'even', 'c': 'odd', 'd': 'even'}
Python
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