66 - for - for循环 - 较慢不建议用

总结

都可以一行一行地读出数据

方式1 iterrows()

import numpy as np
import pandas as pd
df= pd.DataFrame({'a': range(0, 10), 'b': range(10, 20)})
print(df)
for index, row in df.iterrows():
    print (index)
    print (row)
    data = str(row['b'])
    print(data)  # 获得值
    df.loc[index, '修改值的列'] = "new_data"   # 修改值
print(df)

   a   b
0  0  10
1  1  11
2  2  12
3  3  13
4  4  14
5  5  15
6  6  16
7  7  17
8  8  18
9  9  19
0
a     0
b    10
Name: 0, dtype: int64
10
1
a     1
b    11
Name: 1, dtype: int64
11
2
a     2
b    12
Name: 2, dtype: int64
12
3
a     3
b    13
Name: 3, dtype: int64
13
4
a     4
b    14
Name: 4, dtype: int64
14
5
a     5
b    15
Name: 5, dtype: int64
15
6
a     6
b    16
Name: 6, dtype: int64
16
7
a     7
b    17
Name: 7, dtype: int64
17
8
a     8
b    18
Name: 8, dtype: int64
18
9
a     9
b    19
Name: 9, dtype: int64
19
   a   b     修改值的列
0  0  10  new_data
1  1  11  new_data
2  2  12  new_data
3  3  13  new_data
4  4  14  new_data
5  5  15  new_data
6  6  16  new_data
7  7  17  new_data
8  8  18  new_data
9  9  19  new_data

方式2 itertuples()

df= pd.DataFrame({'a': range(0, 10000), 'b': range(10000, 20000)})
count=0
for tup in df.itertuples():
    print(tup)
    print(tup.b)
    print(tup[0])
    print(tup[1::])
    print(type(tup[1:]))
    count+=1
    if count>5:
        break

Pandas(Index=0, a=0, b=10000)
10000
0
(0, 10000)
<class 'tuple'>
Pandas(Index=1, a=1, b=10001)
10001
1
(1, 10001)
<class 'tuple'>
Pandas(Index=2, a=2, b=10002)
10002
2
(2, 10002)
<class 'tuple'>
Pandas(Index=3, a=3, b=10003)
10003
3
(3, 10003)
<class 'tuple'>
Pandas(Index=4, a=4, b=10004)
10004
4
(4, 10004)
<class 'tuple'>
Pandas(Index=5, a=5, b=10005)
10005
5
(5, 10005)
<class 'tuple'>

方式3 zip()

df= pd.DataFrame({'a': range(0, 10000), 'b': range(10000, 20000)})
count=0
for tup in zip(df['a'], df['b']):
    print(tup)
    print(type(tup[1:]))
    count+=1
    if count>5:
        break

(0, 10000)
<class 'tuple'>
(1, 10001)
<class 'tuple'>
(2, 10002)
<class 'tuple'>
(3, 10003)
<class 'tuple'>
(4, 10004)
<class 'tuple'>
(5, 10005)
<class 'tuple'>