How to format data for panel data analysis in python?

Question

I need to conduct time-series analysis on panel data. the data is currently formatted like the table below:

+------+---------+---------+---------+---------+---------+---------+---------+---------+
|      |   Q1    |   Q2    |   Q3    |   Q4    |   Q1    |   Q2    |   Q3    |   Q4    |
+------+---------+---------+---------+---------+---------+---------+---------+---------+
| ID 1 | Value 1 | Value 1 | Value 1 | Value 1 | Value 2 | Value 2 | Value 2 | Value 2 |
| ID 2 | Value 1 | Value 1 | Value 1 | Value 1 | Value 2 | Value 2 | Value 2 | Value 2 |
| ID 3 | Value 1 | Value 1 | Value 1 | Value 1 | Value 2 | Value 2 | Value 2 | Value 2 |
| ID 4 | Value 1 | Value 1 | Value 1 | Value 1 | Value 2 | Value 2 | Value 2 | Value 2 |
+------+---------+---------+---------+---------+---------+---------+---------+---------+

I need the quarterly data on values 1 and 2 to stack like this:

+------+---------+---------+----+
|  ID  |    X    |    Y    | T  |
+------+---------+---------+----+
| ID 1 | Value 1 | Value 2 | Q1 |
| ID 1 | Value 1 | Value 2 | Q2 |
| ID 1 | Value 1 | Value 2 | Q3 |
| ID 1 | Value 1 | Value 2 | Q4 |
| ID 2 | Value 1 | Value 2 | Q1 |
| ID 2 | Value 1 | Value 2 | Q2 |
| ID 2 | Value 1 | Value 2 | Q3 |
| ID 2 | Value 1 | Value 2 | Q4 |
| ID 3 | Value 1 | Value 2 | Q1 |
| ID 3 | Value 1 | Value 2 | Q2 |
| ID 3 | Value 1 | Value 2 | Q3 |
| ID 3 | Value 1 | Value 2 | Q4 |
| ID 4 | Value 1 | Value 2 | Q1 |
| ID 4 | Value 1 | Value 2 | Q2 |
| ID 4 | Value 1 | Value 2 | Q3 |
| ID 4 | Value 1 | Value 2 | Q4 |
+------+---------+---------+----+

The data set is very large, several thousands data points in total.

I'm a beginner, so i was lost.

Answer 1

New Columns Object, stack, reset_index

df.columns = [
    df.columns.to_series().groupby(level=0).cumcount().map({0: 'X', 1: 'Y'}),
    df.columns
]

df.stack().rename_axis(['ID', 'T']).reset_index()

      ID   T        X        Y
0   ID 1  Q1  Value 1  Value 2
1   ID 1  Q2  Value 1  Value 2
2   ID 1  Q3  Value 1  Value 2
3   ID 1  Q4  Value 1  Value 2
4   ID 2  Q1  Value 1  Value 2
5   ID 2  Q2  Value 1  Value 2
6   ID 2  Q3  Value 1  Value 2
7   ID 2  Q4  Value 1  Value 2
8   ID 3  Q1  Value 1  Value 2
9   ID 3  Q2  Value 1  Value 2
10  ID 3  Q3  Value 1  Value 2
11  ID 3  Q4  Value 1  Value 2
12  ID 4  Q1  Value 1  Value 2
13  ID 4  Q2  Value 1  Value 2
14  ID 4  Q3  Value 1  Value 2
15  ID 4  Q4  Value 1  Value 2