Need help for list of list of tuple !

[DeaD_EyE]

# you should avoid names which are used for
# bult-in function/classes
# list is one of them

data = [('aaastring', 245878L, 2475L, 'anotherstring'),
('bbbstring', 7894578L, 456897L, 'yetanother'),
('aaaform', 2445L, 325478L, 'dummy')]

new_list = []

for row in data:
    # row is a tuple
    # a tuple is imuatble
    # you need to create a new one
    # or exchange the tuple with a list
    row = list(row)
    row[0] = 'Replacement for col0 of all rows'
    new_list.append(row)

Content of new_list

Output:
[['Replacement for col0 of all rows', 245878L, 2475L, 'anotherstring'],
['Replacement for col0 of all rows', 7894578L, 456897L, 'yetanother'],
['Replacement for col0 of all rows', 2445L, 325478L, 'dummy']]

Instead of overwriting the first column blindly, you can pass them into a function, which does the work for manipulation based on original data of the object in the first column.

By the way, use Python 3. It gives you super powers.