copying and references

[procho]

a = b makes a copy if strings
a = b copies the reference if lists

(Pdb) ii = [['1003 GPVR_L0003A_1 GS-MT-01', '3570.688']]
(Pdb) iii = ii[0]
(Pdb) iii
['1003 GPVR_L0003A_1 GS-MT-01', '3570.688']
(Pdb) aa = iii[0]
(Pdb) a = 'booo'
(Pdb) iii
['1003 GPVR_L0003A_1 GS-MT-01', '3570.688']
(Pdb) ii
[['1003 GPVR_L0003A_1 GS-MT-01', '3570.688']]
(Pdb) aa = 'boo'
(Pdb) ii
[['1003 GPVR_L0003A_1 GS-MT-01', '3570.688']]
(Pdb) iii
['1003 GPVR_L0003A_1 GS-MT-01', '3570.688']
(Pdb) iii[0] = 'boo'
(Pdb) ii
[['boo', '3570.688']]