Question. how to  reshape in pandas dataframe?
Dataframe looks like below

![image](https://user-images.githubusercontent.com/31833270/55626163-bb1edc80-57e5-11e9-9807-ebc69ff5915a.png)





I have dataframe like above.  which I want to a~t reshape `(a~t, 1)`



I want to reshape dataframe like below ( b~t column is go to under the a column)

```


날짜		역번호	역명	구분    a

2018-01-01	150	서울역	승차	379

2018-01-01	150	서울역	승차	287

2018-01-01	150	서울역	승차	371

2018-01-01	150	서울역	승차	876

2018-01-01	150	서울역	승차	965

....
2008-01-01	152	종각	승차	2920

2008-01-01	152	종각	승차	2290

2008-01-01	152	종각	승차	802

2008-01-01	152	종각	승차	1559
```

like `df = df.reshape(len(data2)*a~t, 1)`

i tried pd.melt but It does not work well.

```
df2 = pd.melt(df, id_vars=["날짜", "역번호", "역명", "구분"], value_name="t")
```
is remove b ~ t but i want insert b~t behind a

dataset is https://drive.google.com/file/d/1Upb5PgymkPB5TXuta_sg6SijwzUuEkfl/view?usp=sharing


