What about this:

>>> mylist = [u'a',u'b',u'c']
>>> str(tuple(map(str, mylist)))
"('a', 'b', 'c')"

if ast.literal_eval is not sufficient and c and r are meant to be non-trivial data objects that should be interpreted, you might consider using asteval (https://github.com/newville/asteval). It can handle evaluating python strings beyond literal strings, including its own symbol table, and avoiding many of the known exploits with using eval().

asteval works like a sand-boxed mini-interpreter with a simple, flat namespace. You would have to add values for c and r to the asteval interpreter, but an example might be:

from asteval import Interpreter
aeval = Interpreter()
aeval('c = 299792458.0')   # speed of light?
aeval('r = c/(2*pi)')      # radius of a circle of circumference c?
                           # note that pi and many other numpy
                           # symbols and functions are built in
input_string = "[[1,2,3],[c,4,r]]"

out = aeval(input_string)
print(out)

which will give

[[1, 2, 3], [299792458.0, 4, 47713451.59236942]]

Alternatively, you could have set c directly from Python with

aeval.symtable['c'] = 299792458.0

There are many known-to-be-unsafe things that asteval refuses to do, but there are also many things it can do that ast.literal_eval cannot. Of course, if you're accepting code from user input, you should be very careful.

Using the eval() function along with a list comprehension we can try:

inp = ["[21049090, 'AARTIIND22AUGFUT', 'AARTIIND', 850, 1793]", "[21049346, 'ABB22AUGFUT', 'ABB', 250, 3329]"]
output = [eval(x) for x in inp]
print(output)

This prints:

[
    [21049090, 'AARTIIND22AUGFUT', 'AARTIIND', 850, 1793],
    [21049346, 'ABB22AUGFUT', 'ABB', 250, 3329]
]

Yes, there is. You can use the following list-comprehention.
newArray = [x[:6] for x in y]

Slicing has the following syntax: list[start:end:step]

Arguments:

start - starting integer where the slicing of the object starts
stop - integer until which the slicing takes place. The slicing stops at index stop - 1.
step - integer value which determines the increment between each index for slicing

Examples:

    list[start:end] # get items from start to end-1
    list[start:]    # get items from start to the rest of the list
    list[:end]      # get items from the beginning to the end-1 ( WHAT YOU WANT )
    list[:]         # get a copy of the original list

if the start or end is -negative, it will count from the end

    list[-1]    # last item
    list[-2:]   # last two items
    list[:-2]   # everything except the last two items
    list[::-1]  # REVERSE the list

Demo:
let's say I have an array = ["doctorWho","Daleks","Cyborgs","Tardis","SonicSqrewDriver"]

and I want to get the first 3 items.

>>> array[:3] # 0, 1, 2 (.. then it stops)
['doctorWho', 'Daleks', 'Cyborgs']

(or I decided to reverse it):

>>> array[::-1]
['SonicSqrewDriver', 'Tardis', 'Cyborgs', 'Daleks', 'doctorWho']

(now i'd like to get the last item)

>>> array[-1]
'SonicSqrewDriver'

(or last 3 items)

>>> array[-3:]
['Cyborgs', 'Tardis', 'SonicSqrewDriver']

I would do:

import re

regx = re.compile('{\s*file\s*:\s*([^,\s]+)\s*'
                  ','
                  '\s*directory\s*:\s*([^}\s]+)\s*}')

file_info = ['{file:C:\\samples\\123.exe, directory  :  C:\\}',
             '{  file:  C:\\samples\\345.exe,directory:C:\\}'
             ]

for item in file_info:
    print '%r\n%s\n' % (item,
                        regx.search(item).groups())

result

'{file:C:\\samples\\123.exe, directory  :  C:\\}'
('C:\\samples\\123.exe', 'C:\\')

'{  file:  C:\\samples\\345.exe,directory:C:\\}'
('C:\\samples\\345.exe', 'C:\\')