数据结构

fruits = ["orange", "apple", "banana"]
fruits.append("kiwi")
fruits.sort()
fruits.pop()         # 弹末尾
fruits.index("apple")
fruits.count("apple")
fruits.reverse()
fruits.copy()
fruits.clear()

squares = [x * x for x in range(10)]
flat = [x for row in matrix for x in row]

matrix = [
    [1, 2, 3],
    [4, 5, 6],
]
transposed = [[row[i] for row in matrix] for i in range(3)]
# [[1, 4], [2, 5], [3, 6]]

a = [1, 2, 3, 4, 5]
del a[0]        # [2, 3, 4, 5]
del a[1:3]      # [2, 5]
del a           # 删除变量本身

t = 1, 2, 3
t = (1,)          # 单元素元组
empty = ()
nested = (1, (2, 3))
x, y = (1, 2)     # 解包

s = {1, 2, 3}
s.add(4)
s.remove(2)
s | {5, 6}        # 并集
s & {3, 4, 5}     # 交集
s - {3}           # 差集
1 in s            # True

{x for x in "abracadabra" if x in "abc"}
# {'a', 'b', 'c'}

d = {"one": 1, "two": 2}
d["three"] = 3
d.get("four", 0)    # 0
d.keys()
d.values()
d.items()
"one" in d
del d["one"]
d.pop("two")
d.update({"x": 0})

{x: x * x for x in range(5)}

for k, v in d.items():
    print(k, v)

# 同时遍历键值
for k, v in d.items(): ...

# 同时遍历多个序列
for a, b in zip(L1, L2): ...

# 反向
for x in reversed(seq): ...

# 排序
for x in sorted(s, key=...): ...

import copy
a = [[1, 2], [3, 4]]
b = a              # 引用同一对象
c = a.copy()       # 浅拷贝（外层新，内层共享）
d = copy.deepcopy(a)  # 深拷贝
a[0].append(99)
b[0]   # [1, 2, 99]
c[0]   # [1, 2, 99]  ← 浅拷贝受影响
d[0]   # [1, 2]      ← 深拷贝独立