Python“玩”数据的利器!

Series

Series是一个能够容纳任意数据类型的带标记的一维数组。(Series is a one-dimensional labeled array capable of holding any data type (integers, strings, floating point numbers, Python objects, etc.). The axis labels are collectively referred to as the index. )

官方文档

初始化

从map初始化

>>> import numpy as np
>>> s = pd.Series(np.random.randn(5), index=["a", "b", "c", "d", "e"])
>>> s
a    1.677571
b    0.277393
c    0.945309
d    1.276764
e    0.686729
dtype: float64

从数组初始化

>>> data = np.array([(1, 2, 3), (4, 5, 6), (7, 8, 9)],
...                 dtype=[("a", "i4"), ("b", "i4"), ("c", "i4")])
>>> s = pd.Series(data, columns=['c', 'a'])
...
>>> df3
   c  a
0  3  1
1  6  4
2  9  7

转化为list

>>> s.tolist()
[1.6775712053562015, 0.2773932925846383, 0.9453092483775857, 1.276764091946826, 0.6867285857318276]

转化为dict

>>> s = pd.Series([1, 2, 3, 4])
>>> s.to_dict()
{0: 1, 1: 2, 2: 3, 3: 4}

>>> from collections import OrderedDict, defaultdict
>>> s.to_dict(OrderedDict)
OrderedDict([(0, 1), (1, 2), (2, 3), (3, 4)])

>>> dd = defaultdict(list)
>>> s.to_dict(dd)
defaultdict(<class 'list'>, {0: 1, 1: 2, 2: 3, 3: 4})