python transform complex list of lists into a string

Question

I have a complex list of lists that looks like that :

[[['MARIA DUPONT',
   ' infos : ',
   [' age = 28',
    ' yeux = bleus',
    ' sexe = femme']],
  [' + ']],
 [['PATRICK MARTIN',
   ' infos : ',
   [' age = 53',
    ' yeux = marrons',
    ' sexe = homme']],
  [' + ']],
 [['JULIE SMITH',
   ' infos : ',
   [' age = 17',
    'yeux = verts',
    'sexe = femme']],
  [' fin ']]]

I am trying to transform it into a string. At the end I want to print that :

MARIA DUPONT,
 infos :
 age = 28 
 yeux = bleus 
 sexe = femme 

 + 

PATRICK MARTIN
 infos :
 age = 53
 yeux = marrons
 sexe = homme

 + 

JULIE SMITH
 infos :
 age = 17
 yeux = verts
 sexe = femme

 fin

My real data are more complicated and I have lists into level 5. So I am looking for a way to solve the problem I explained to be able to adapt it and apply it to my real data.

I am trying with ''.join(list) and ''.join(x for x in list)

But in both cases I have the error TypeError: list indices must be integers or slices, not list

I've tryed other ways but now I'm confused and I didn't found a good solution to reach my goal.

Any help would be appreciated, and thanks in advance. (and sorry for my bad english!)

Ajax1234 · Accepted Answer · 2020-05-07 15:40:38Z

1

You can use str.join with a single pass over the lists:

data = [[['MARIA DUPONT', ' infos : ', [' age = 28', ' yeux = bleus', ' sexe = femme']], [' + ']], [['PATRICK MARTIN', ' infos : ', [' age = 53', ' yeux = marrons', ' sexe = homme']], [' + ']], [['JULIE SMITH', ' infos : ', [' age = 17', 'yeux = verts', 'sexe = femme']], [' fin ']]]
r = '\n'.join('\n'.join([a, b, *c, f'\n{k}\n']) for [a, b, c], [k] in data)

Output:

MARIA DUPONT
 infos : 
 age = 28
 yeux = bleus
 sexe = femme

 + 

PATRICK MARTIN
 infos : 
 age = 53
 yeux = marrons
 sexe = homme

 + 

JULIE SMITH
 infos : 
 age = 17
 yeux = verts
 sexe = femme

 fin

If your lists are arbitrarily nested, then you can use recursion with a generator:

def flatten(d):
  if isinstance(d, str):
     yield d
  else:
     yield from [i for b in d for i in flatten(b)]

print('\n'.join(flatten(data)))

answered May 7, 2020 at 15:40

Ajax1234

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1 Comment

mathilde Over a year ago

Thank you that is exactly what I needed, I applied it into my real data and it works perfectly !

Midriaz · Accepted Answer · 2020-05-07 14:49:34Z

1

.join() won't work with a list in the list. I can offer you a solution based on recursion.

def list_to_str(_list):
    result = ""
    if isinstance(_list, list):   
        for l in _list:
            result += list_to_str(l)
    else:
        result += _list
    return result

result_string = list_to_str(your_list)

print(result_string)

answered May 7, 2020 at 14:49

Midriaz

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Comments

Chun · Accepted Answer · 2020-05-07 14:55:07Z

1

I can't tell if you have a list with varying levels of lists but if so, you would probably need a conditional to see if the list goes further and recursively iterate the list.

def convert_list(dataset):
    result = ''
    for element in dataset:
        if isinstance(element, list):
            result += convert_list(element)
        else:
            result += str(element)
    return result

This will not print the newlines you want but it does return the list as a string.

answered May 7, 2020 at 14:55

Chun

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Comments

haja · Accepted Answer · 2020-05-07 16:05:44Z

Write a recursive function to get inside your lists like below:

def print_data(input_list):

    for obj in input_list:
        if isinstance(obj, list):
            print_data(obj)
        else:
            print(obj)



input_list = [[['MARIA DUPONT',
                    ' infos : ',
                    [' age = 28',
                     ' yeux = bleus',
                     ' sexe = femme']],
                   [' + ']],
                  [['PATRICK MARTIN',
                    ' infos : ',
                    [' age = 53',
                     ' yeux = marrons',
                     ' sexe = homme']],
                   [' + ']],
                  [['JULIE SMITH',
                    ' infos : ',
                    [' age = 17',
                     'yeux = verts',
                     'sexe = femme']],
                   [' fin ']]]
print_data(input_list)

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