How can I rearrange df as the nodes index in pytorch geometric manner?

[uqlsmey]

How can I rearrange df as the nodes index in pytorch geometric manner?

This is my code

data = {'Source': ['Rainfall', 'SP2', 'SP2', 'Inflow','Rainfall','Inflow', 'Inflow', 'Inflow','SWT','SP1','SP1','SWD'],
       'Target': ['SP1', 'Evp', 'Outflow', 'SP2','SWD','SWD', 'SP2','SP1','SP1','SP2','Evp','Loss']}  
df = pd.DataFrame(data)
nodes = pd.concat([df['Source'], df['Target']]).unique()
node_indices = {node: i for i, node in enumerate(nodes)}
df['Source'] = df['Source'].map(node_indices)
df['Target'] = df['Target'].map(node_indices)

My goal is to generate the following outputs:

Source Source Source Target Target Source Source Target Target
4 4 4 4 4 1 1 1 1
0 2 3 1 6 2 2 6 7
Label Rainfall Inflow SWT SP2 Evp Inflow Inflow Evp Outflow