Print mixed list without brackets in a single row

Question

I have a list in Python.

I have tried to set print(*arr, sep=",") refer "Print list without brackets in a single row". But my real problem is:

### List
num = 2
arr= [0, "txt", 4, 5, [3,4, num]]
# print full
print(arr)

# print an arr without brackets
print(*arr, sep=",")

Expected result: 0,txt,4,5,3, 4, 2
Actual result: 0,txt,4,5,[3, 4, 2]

The compiler does not remove brackets from sub-list. Please give me advice to fix it. Thanks!

Not quite a dupe, but applicable: https://stackoverflow.com/q/2158395/2988730 — Mad Physicist, Jan 18 '19 at 04:40

Dillon Davis · Answer 1 · 2019-01-18T04:55:43.593

0

Use a function to flatten the list first, and then print the new list.

def flatten(original, iterables=[list]):
    out = []
    for val in original:
        if type(val) not in iterables:
            out.append(val)
        else:
            out += flatten(val)
    return out


print(flatten(arr))

Here I explicitly specify type(val) != list so that it will not attempt to split up your strings, but will flatten sub lists. Additionally, this method will handle nested lists of any depth.

Result:

>>> print(flatten(arr))
[0, 'txt', 4, 5, 3, 4, 2]

You can also pass a second argument iterables, which is a list containing what iterable types you wish to flatten. This can include list, tuple, or anything else. Here I default to list since that's what your example requires.

edited Jan 18 '19 at 04:55

answered Jan 18 '19 at 04:45

Dillon Davis

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This is cool but what about `str(arr).replace('[','').replace(']','').replace("'",'').replace(")",'').replace("(", '')` ? – mrtpk Jan 18 '19 at 04:47
2

Fails on tuples. – TigerhawkT3 Jan 18 '19 at 04:48
@tpk That is simpler, but will fail if the string elements contain backets – Dillon Davis Jan 18 '19 at 04:49
@DillonDavis Correct! – mrtpk Jan 18 '19 at 04:51
1

@TigerhawkT3 I assumed that the only iterable that OP wants to flatten are lists based on the example, but I may be interpreting it too literally. In that case, `type(val) not in list_of_iterables_to_flatten` would work. – Dillon Davis Jan 18 '19 at 04:51
@TigerhawkT3 updated / generalized my answer with support for other iterables. Thanks for bringing it to my attention. – Dillon Davis Jan 18 '19 at 04:57
It's exhaustively covered in the duplicate anyway. – TigerhawkT3 Jan 18 '19 at 04:58
@DillonDavis Thank you very much! It's very useful. – Allerwill Lee Jan 18 '19 at 05:03
@AllerwillLee if this solves your problem, feel free to accept it so that others can see that it has been solved. – Dillon Davis Jan 18 '19 at 06:23

score 0 · Answer 2 · answered Jan 18 '19 at 05:03

try this for removing nested bracket only from the list:

num = 2    
arr = [0, "txt", 4, 5, [3,4, num]]    
output = []     
def removeBracket(arr): 
    for i in arr: 
        if type(i) == list: 
            removeBracket(i) 
        else: 
            output.append(i)   
removeBracket(arr)
print(output) # [0, 'txt', 4, 5, 3, 4, 2]

Print mixed list without brackets in a single row

2 Answers2