import pandas as pd
s = pd.Series([1,3,6,2])
s
# 0 1
# 1 3
# 2 6
# 3 2
# dtype: int64
s.index
# RangeIndex(start=0, stop=4, step=1)
s.values
# array([1, 3, 6, 2], dtype=int64)
s1 = pd.Series([1,3,6,2], index=['a', 'b', 'c', 'd'])
s1
# a 1
# b 3
# c 6
# d 2
# dtype: int64
s.index
# Index(['a', 'b', 'c', 'd'], dtype='object')
s[s<3]
# a 1
# d 2
# dtype: int64
s*4
# a 4
# b 12
# c 24
# d 8
# dtype: int64
import numpy as np
np.mean(s) # 3.0
s.mean() # 3.0
s.max() # 6
s.index # Index(['a', 'b', 'c', 'd'], dtype='object')
'e' in s.index # False
s = pd.Series({'a': 1, 'b': 9, 'c': 4})
s
# a 1
# b 9
# c 4
# dtype: int64
s = pd.Series({'a': 1, 'b': 9, 'c': 4}, index=['a', 'b', 'd'])
s
# a 1
# b 9
# d NaN
# dtype: int64
s[s.isnull()]
#d NaN
#dtype: float64
自动按照索引对齐
s
# a 1.0
# b 9.0
# d NaN
# dtype: float64
s1
# a 1
# b 3
# c 6
# d 2
# dtype: int64
s + s1
# a 2.0
# b 12.0
# c NaN
# d NaN
# dtype: float64
s.notnull()
# a True
# b True
# d False
# dtype: bool
s
# a 1.0
# b 9.0
# d NaN
# dtype: float64
s['a']
# 1.0
s[['a', 'b']]
# a 1.0
# b 9.0
# dtype: float64
s1
# a 1
# b 3
# c 6
# d 2
# dtype: int64
s1['a': 'c']
# a 1
# b 3
# c 6
# dtype: int64
s['a'] = 1000
s
# a 1000.0
# b 9.0
# d NaN
# dtype: float64
s
# a 1000.0
# b 9.0
# d NaN
# dtype: float64
s[s.isnull()]
# d NaN
# dtype: float64
s[~s.isnull()]
# a 1000.0
# b 9.0
# dtype: float64
s[s.notnull()]
# a 1000.0
# b 9.0
# dtype: float64
取出一列,就是一个series
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