Datatype (dict, list)

Number vs. String

Int, float, complex vs. 문자열

Built-in Collections

{set} vs. {: Dictionary}

(Tuple) vs. [List]

methods

#=== Using list slicing
### Extract sublists with list slicing
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
first_five = numbers[:5]
last_five = numbers[5:]
middle_five = numbers[3:8]
evens = numbers[1::2]
odds = numbers[::2]
reversed_numbers = numbers[::-1]

#=== Using string slicing
### Extract substrings with string slicing
name = 'Alice'
first_three = name[:3]
last_three = name[2:]
middle_three = name[1:4]
evens = name[1::2]
odds = name[::2]
reversed_name = name[::-1]

#=== Using list unpacking
### Unpack lists with list unpacking
numbers = [1, 2, 3]
a, b, c = numbers

#=== Using dictionary unpacking
### Unpack dictionaries with dictionary unpacking
person = {'name': 'Alice', 'age': 24}
name, age = person.values()

#=== Using set unpacking
### Unpack sets with set unpacking
numbers = {1, 2, 3}
a, b, c = numbers

#=== Using f-string
### Format strings with f-string
name = 'Alice'
age = 24
formatted_string = f'My name is {name} and I am {age} years old.'

name = 'Alice'
name_upper = name.upper()
name_lower = name.lower()
name_title = name.title()
name_capitalize = name.capitalize()
name_swapcase = name.swapcase()
name_strip = name.strip()
name_lstrip = name.lstrip()
name_rstrip = name.rstrip()
name_replace = name.replace('A', 'Z')
name_split = name.split('l')
name_join = '-'.join(['A', 'l', 'i', 'c', 'e'])

slicing

#=== Using sets to store unique values 
### fileter distinct value, Set은 unordered key값만 있는 dictionary
numbers = [2, 1, 1, 1, 2, 3, 3, 4, 5, 6, 7, 8, 5, 5]
numbers = set(numbers)     #  {1, 2, 3, 4, 5, 6, 7, 8}

june_dates = [datetime(2024, 6, day) for day in range(1, 31)]
random_dates = random.sample(june_dates, k=16)  # unordered dates, unique
random_dates = random.choices(june_dates, k=16)  # unordered dates, un-unique
my_dates = set(random_dates)

numbers.add(11)
numbers.discard(5)

numbers.remove(6)     # 없는 값을 지우려고 하면 에러 발생
numbers.clear()

#=== Using list methods
### Manipulate lists with list methods
numbers = [1, 2, 3, 4, 5]
numbers.append(6)
numbers.insert(0, 0)
numbers.extend([7, 8, 9])
numbers.pop(0)
numbers.sort()

numbers.remove(0)
numbers.clear()

#=== Using dictionary methods
### Manipulate dictionaries with dictionary methods
person = {'name': 'Alice', 'age': 24}
person['name'] = 'Bob'
person['age'] = 50
person['city'] = 'New York'
person.pop('city')
person.popitem()
person.clear()

Immutable vs. Mutable

 변수가 담고 있는 object의 속성에 따라 결정

 json vs. dictionary

json과 dictionary 모두 KEY, VALUE인데 왜 굳이 json 일까

import json

dictVal = {'name':'johnDou', 'age':16, 'job':True}

jsonVal = json.dumps(dictVal)
# '{"name": "johnDou", "age": 16, "job": true}'

dictVal2 = json.loads(jsonVal)
# {'name': 'johnDou', 'age': 16, 'job': True}

dictVal['name']
# 'johnDou'
jsonVal['name']
# TypeError: string indices must be integers