appending to a list of lists

Question

I want to add an additional time of '10:01' for J Petry to the following list:

PlayerMatrix = [["['J. Petry', '24:17']"], ["['G. Chase', '11:03']"]]

so I want to get output of ......

PlayerMatrix = [["['J. Petry', '24:17', '10:01']"], ["['G. Chase', '11:03']"]]

I've tried

PlayerMatrix[0].append("10:01")

and this gives me.......

PlayerMatrix = [["['J. Petry', '24:17']", '10:01'], ["['G. Chase', '11:03']"]]

ie instead of adding it to the first list it creates a second list. There must be something simple I'm doing wrong.....

Answer 1

As your element are string you can not use append for this aim . you can use ast module :

>>> import ast
>>> a=ast.literal_eval(PlayerMatrix[0][0])
>>> a
['J. Petry', '24:17']
>>> a.append("10:01")
>>> a
['J. Petry', '24:17', '10:01']

and then you can convert the result to string :

>>> str(a)
"['J. Petry', '24:17', '10:01']"

Answer 2

Odd format you have there. The solution:

PlayerMatrix = [["['J. Petry', '24:17']"], ["['G. Chase', '11:03']"]]
# used to serialize/deserialize - probably should have functions for that
import json
def append_to_player(matrix, player, t):
    # parse your format
    parsed = [json.loads(v[0].replace("'", '"')) for v in matrix]
    for p in parsed:
        # add the value to 'player'
        if p[0] == player:
            p.append(t)
    # reformat and return
    return [[json.dumps(v).replace('"', "'")] for v in parsed]

# TEST
# alter matrix by assignment of result
PlayerMatrix = append_to_player(PlayerMatrix, "J. Petry", '13;37')
print PlayerMatrix