connect_individuals.py

column_edge = 'Phone number'
column_ID = 'ID'

data_to_merge = df[[column_ID, column_edge]].dropna(subset=[column_edge]).drop_duplicates() # select columns, remove NaN

# To create connections between people who have the same number,
# join data with itself on the 'ID' column.
data_to_merge = data_to_merge.merge(
    data_to_merge[[column_ID, column_edge]].rename(columns={column_ID:column_ID+"_2"}), 
    on=column_edge
)