data ={'a':[11,22,33,44],'b':['aa','bb','cc','dd'],'c':[9,8,7,6],'d':[1,2,3,4]}
df = DataFrame(data)
df
a
b
c
d
0
11
aa
9
1
1
22
bb
8
2
2
33
cc
7
3
3
44
dd
6
4
iloc：通過行/列號選取數據
df.iloc[0]#選取第0行數據
a 11
b aa
c 9
d 1
Name: 0, dtype: object
df.iloc[0:2]#選取多行
a
b
c
d
0
11
aa
9
1
1
22
bb
8
2
df.iloc[:,[1]]#也可以按照列號選取某列 選取第2列
b
0
aa
1
bb
2
cc
3
dd
df.iloc[0:1,[1]]#可以按照行號選取某行某列 選取第0行 第2列
b
0
aa
df.iloc[0:2,[0,1]]#可以按照行號選取多行多列 選取第0~2行 第0～2列
a
b
0
11
aa
1
22
bb
loc通過標簽選取數據
df.loc[0]#選取第1行 因為第1行的行號是0所以和iloc效果相同
a 11
b aa
c 9
d 1
Name: 0, dtype: object
data ={'a':[11,22,33,44],'b':['aa','bb','cc','dd'],'c':[9,8,7,6],'d':[1,2,3,4]}
df1 = DataFrame(data,index =['a','b','c','d'])
df1
a
b
c
d
a
11
aa
9
1
b
22
bb
8
2
c
33
cc
7
3
d
44
dd
6
4
df1.loc['b']#選取第b行
a 22
b bb
c 8
d 2
Name: b, dtype: object
df1.loc['b':]#選取多行
a
b
c
d
b
22
bb
8
2
c
33
cc
7
3
d
44
dd
6
4
df1.loc[:,['a']]#通過標簽選取某列
a
a
11
b
22
c
33
d
44
df1.loc[:,['a','b']]#通過標簽選取多列
a
b
a
11
aa
b
22
bb
c
33
cc
d
44
dd
df1.loc['a',['b','c']]#通過標簽選取某行某列
b aa
c 9
Name: a, dtype: object
按照條件選取數據
df1.loc[df1['a']==11]#通過單個條件選取數據
a
b
c
d
a
11
aa
9
1
df1.loc[(df1['a']==11)&(df1['d']==1)]#通過單多個條件選取數據
a
b
c
d
a
11
aa
9
1
ix 簡單粗暴 混合使用
也就是說 ix把iloc和loc語法綜合了，愛用哪個用哪個，不過會報個warning
df #再看下dataframe
a
b
c
d
0
11
aa
9
1
1
22
bb
8
2
2
33
cc
7
3
3
44
dd
6
4
df.ix[1]#可以像iloc通過行號選取
/Users/anaconda/anaconda3/lib/python3.7/site-packages/ipykernel_launcher.py:1: FutureWarning:
.ix is deprecated. Please use
.loc for label based indexing or
.iloc for positional indexing
See the documentation here:
http://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#ix-indexer-is-deprecated
"""Entry point for launching an IPython kernel.
a 22
b bb
c 8
d 2
Name: 1, dtype: object
df1
a
b
c
d
a
11
aa
9
1
b
22
bb
8
2
c
33
cc
7
3
d
44
dd
6
4
df1.ix['a']#可以像loc通過標簽選取
/Users/anaconda/anaconda3/lib/python3.7/site-packages/ipykernel_launcher.py:1: FutureWarning:
.ix is deprecated. Please use
.loc for label based indexing or
.iloc for positional indexing
See the documentation here:
http://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#ix-indexer-is-deprecated
"""Entry point for launching an IPython kernel.
a 11
b aa
c 9
d 1
Name: a, dtype: object
df1.ix[3,3]#通過行號選取指定位置的數據
/Users/anaconda/anaconda3/lib/python3.7/site-packages/ipykernel_launcher.py:1: FutureWarning:
.ix is deprecated. Please use
.loc for label based indexing or
.iloc for positional indexing
See the documentation here:
http://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#ix-indexer-is-deprecated
"""Entry point for launching an IPython kernel.
/Users/anaconda/anaconda3/lib/python3.7/site-packages/pandas/core/indexing.py:961: FutureWarning:
.ix is deprecated. Please use
.loc for label based indexing or
.iloc for positional indexing
See the documentation here:
http://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#ix-indexer-is-deprecated
return getattr(section, self.name)[new_key]
4
df1.ix['a','a']#通過標簽選取指定位置的數據
/Users/anaconda/anaconda3/lib/python3.7/site-packages/ipykernel_launcher.py:1: FutureWarning:
.ix is deprecated. Please use
.loc for label based indexing or
.iloc for positional indexing
See the documentation here:
http://pandas.pydata.org/pandas-docs/stable/user_guide/indexing.html#ix-indexer-is-deprecated
"""Entry point for launching an IPython kernel.
11
