在一列中循环多个值

Question

有人可以请我告诉我如何遍历数据框列中的多个值。

例子：

col1 col2 
High street qwe.723,qwe.2,qwe.17,qwe.1000,qwe.23 
Must street qwe.34,qwe.17,qwe.1000,qwe.23 

我想有以下输出：

High street 
qwe.723 
High street 
qwe.2 
High street 
qwe.17 
High street 
qwe.1000 
High street 
qwe.23 

Must street 
qwe.34 
Must street 
qwe.17 
Must street 
qwe.1000 
Must street 
qwe.23 

我尝试：

lines = open('file.txt','r') 
for line in lines: 
    line=line.strip().split('\t') 
    vals=line[1].split(',') 
    for val in vals: 
     print(line[0],'\n',val) 

Answer 1

试试这个：

In [136]: df 
Out[136]: 
      col1         col2 
0 High street qwe.723,qwe.2,qwe.17,qwe.1000,qwe.23 
1 Must street   qwe.34,qwe.17,qwe.1000,qwe.23 

In [137]: df.set_index('col1').col2.str.split(',', expand=True).stack().reset_index(level=1, drop=1).to_frame('col2').reset_index().stack() 
    ...: 
Out[137]: 
0 col1 High street 
    col2  qwe.723 
1 col1 High street 
    col2   qwe.2 
2 col1 High street 
    col2   qwe.17 
3 col1 High street 
    col2  qwe.1000 
4 col1 High street 
    col2   qwe.23 
5 col1 Must street 
    col2   qwe.34 
6 col1 Must street 
    col2   qwe.17 
7 col1 Must street 
    col2  qwe.1000 
8 col1 Must street 
    col2   qwe.23 
dtype: object 

我敢肯定，必须有一个更好的方式来做到这一点...

Answer 2

还有一句：

(df.set_index('col1') 
    .col2.str.split(',', expand=True) 
    .stack() 
    .reset_index(level=-1, drop=True) 
    .to_csv('output.txt',sep='\n') 

Answer 3

因为我是玩弄具有和numpy
超快速的乐趣！

import cytoolz 

c2 = np.core.defchararray.split(df.col2.values.astype('str'), ',') 
col1 = df.col1.values.repeat([len(c) for c in c2.tolist()]) 
col2 = list(cytoolz.concat(c2)) 
np.stack([col1, col2]).ravel('F') 

array(['High street', 'qwe.723', 'High street', 'qwe.2', 'High street', 
     'qwe.17', 'High street', 'qwe.1000', 'High street', 'qwe.23', 
     'Must street', 'qwe.34', 'Must street', 'qwe.17', 'Must street', 
     'qwe.1000', 'Must street', 'qwe.23'], dtype=object) 

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