Python Dictionary Tips: Secrets to Improve Code Efficiency

1. Creation of dictionary

1. Literal creation of dictionary:

my_dict = {"name": "John Doe", "age": 30, "city": "New York"}

2. Built-in function creation of dictionary:

my_dict = dict(name="John Doe", age=30, city="New York")

3. Deductive creation of dictionary:

my_dict = {key: value for key, value in zip(["name", "age", "city"], ["John Doe", 30, "New York"])}

2. Modification of dictionary

1. Add key-value pairs:

my_dict["job"] = "Software Engineer"

2. Modify key-value pairs:

my_dict["age"] = 31

3. Delete key-value pairs:

del my_dict["city"]

3. Dictionary search

1. Get the value by key:

value = my_dict["name"]

2. Use the get() method to get the value (if the key does not exist, return the default value):

value = my_dict.get("phone", "Not provided")

3. Check if the key exists:

if "email" in my_dict:
# 键存在，执行某些操作

4. Dictionary traversal

1. Traverse keys:

for key in my_dict:
print(key)

2. Traverse keys and values:

for key, value in my_dict.items():
print(key, value)

3. Iterate over keys and values ​​(using dict.values() and dict.keys()):

for value in my_dict.values():
print(value)

for key in my_dict.keys():
print(key)

5. Other techniques

1. Merge of dictionaries:

my_dict1 = {"name": "John Doe", "age": 30}
my_dict2 = {"city": "New York", "job": "Software Engineer"}

my_dict3 = {**my_dict1, **my_dict2}

2. Copy of dictionary:

my_dict_copy = my_dict.copy()

3. Sort of dictionary:

sorted_dict = dict(sorted(my_dict.items(), key=lambda item: item[1]))

Mastering these skills can help you use python dictionaries more efficiently and improve the quality and performance of your code.

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