Pandas 数据框转换

Question

I am new to python and have a need where I need to trasform below pandas dataframe -

type           c1                 c2             c3
 a             9                  10.0          -11.11
 b             162                165.0         -1.85
 c             16                 15.0           6.25

to this format-

      a                  b                 c
c1   c2    c3      c1    c2    c3    c1   c2   c3
9   10.0 -11.11    162  165 -1.85    16  15.0  6.25

I have tried various combinations of transpose, multi-indexing and pivoting but no luck, could you please help me find the solution for this.

Thanks!

Answer 1

Here's one way:

df1 = df.set_index('type').stack()
df = pd.DataFrame(df1.values.reshape(-1,len(df1)), columns = df1.index)

Alternative:

df = df.set_index('type').stack().to_frame().T

OUTPUT:

type    a                   b                  c            
       c1    c2     c3     c1     c2    c3    c1    c2    c3
0     9.0  10.0 -11.11  162.0  165.0 -1.85  16.0  15.0  6.25

Answer 2

Try this:

result = (
    df.set_index('type')
      .stack()
      .to_frame()
      .T
)

---

If you feel overwhelmed by the chain of operations, try one line a time to see its effect:

Step 1:

(
    df.set_index('type')
      .stack()
    # .to_frame()
    # .T
)

Step 2:

(
    df.set_index('type')
      .stack()
      .to_frame()
    # .T
)

And so on...