列表中的python合并列表

Question

im pretty nooby at python. However, i am trying to merge a list of data lists or a list with a element thats inside a list. Anyways, in essence it looks like this...

example:

data_list = ["x, cat, x, 8, ["10"]"]

and i want it to look like this...

data_list = ["x, cat, x, 8, 10"]

i have tried to make a new list and .append() it to that but the result does not seem any different. itertools breaks up every item into a string separated by a comma.

using reduce(lambda x,y: x+y,data_list) only removes the outer brackets so it looks like this when printed to the shell:

data_list = x, cat, x, 8, ["10"]

is there a way that i can remove the inner brackets using lambda ? or any method that give me the same outcome?

Answer 1

It looks like you are trying to flatten a list with some elements which are lists and some which are not. The following does what you want, assuming that your nested lists have only one element.

data_list = ["x", "cat", "x", 8, ["10"]]

def Strip(x):
   if isinstance(x, list):
     return x[0]
   return x

newlist = [Strip(x) for x in data_list]

print newlist

Here's another, perhaps more readable solution that will handle nested lists with multiple elements, but not multiple layers of nesting.

data_list = ["x", "cat", "x", 8, ["10",10]]

new_list = []
for x in data_list:
  if isinstance(x,list):
    new_list += x
  else:
    new_list.append(x)

print new_list

If we assume that data_list starts out as as list containing a single string rather than a list object, we can convert it into a list first before using the methods above.

import ast
data_list = ast.literal_eval(data_list[0])

and convert it back after we are done:

new_list = [new_list.__str__()]

Answer 2

Using replace, join and map:

print ["".join(map(lambda x: x.replace('[','').replace(']','').replace('"',''), ''.join(data_list).split()))]

output:

["x,cat,x,8,10"]