My question is similar to [this question](https://stackoverflow.com/questions/12329853/how-to-rearrange-pandas-column-sequence). In answers of that question i saw few ways to do what i am trying to do below. But answers are old and i feel that there might be a fast and an efficient way to do what i am looking for. 

```
import pandas as pd

df =pd.DataFrame({'a':[1,2,3,4],'b':[2,4,6,8]})
df['x']=df.a + df.b
df['y']=df.a - df.b
df
   a  b   x  y
0  1  2   3 -1
1  2  4   6 -2
2  3  6   9 -3
3  4  8  12 -4

```

Now I want to move x and y columns to beginning. I can always do below. 

```
df = df[['x','y','a','b']]
df
    x  y  a  b
0   3 -1  1  2
1   6 -2  2  4
2   9 -3  3  6
3  12 -4  4  8

```

But I don't want that solution. I want an efficient solution that would move columns x and y to beginning without mentioning names of other columns as my dataframe is going to change and i might not know names of all the columns