如何在pandas多索引中生成leters实例数？

import pandas as pd

# 创建多级索引
idx = pd.Index([['A', 'A', 'B', 'B'], ['a', 'b', 'a', 'b']])

# 获取每个层级的索引
levels = [idx.get_level_values(level) for level in range(idx.nlevels)]

# 计算每个层级的不同值的个数
counts = [len(pd.unique(level)) for level in levels]

print(counts)  # 输出 [2, 2]

import pandas as pd

# 创建多级索引
idx = pd.MultiIndex.from_tuples([('A', 'a'), ('A', 'b'), ('B', 'a'), ('B', 'b')])

# 获取每个层级的索引
levels = [idx.get_level_values(level) for level in range(idx.nlevels)]

# 计算每个层级的不同值的个数
counts = [len(pd.unique(level)) for level in levels]

print(counts)  # 输出 [2, 2]