Adding a string to an array adds all characters separately

Question

Any suggestion how to merge it better so the dual digits numbers does not split? Sorry for bad english.

def merge(strArr):
    newList = []
    for x in range(len(strArr)):
        newList += strArr[x]
    return newList

array_test = ["1, 3, 4, 7, 13", "1, 2, 4, 13, 15"]
print(merge(array_test))

output =['1', ',', ' ', '3', ',', ' ', '4', ',', ' ', '7', ',', ' ', '1', '3', '1', ',', ' ', '2', ',', ' ', '4', ',', ' ', '1', '3', ',', ' ', '1', '5']`

expected output= [1,2,3,4,7,13,1,2,4,13,15]

because you take each inner string and add each character of each inner string to your return-list. — Patrick Artner
– Patrick Artner, Commented Apr 18, 2020 at 15:28

Shubham Sharma · Accepted Answer · 2020-04-18 15:27:49Z

3

Using list comprehension:

merged_arr = [n for s in array_test for n in s.split(", ")]
print(merged_arr)

This prints:

['1', '3', '4', '7', '13', '1', '2', '4', '13', '15']

answered Apr 18, 2020 at 15:27

Shubham Sharma

71.8k6 gold badges26 silver badges58 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Louis Lac · Accepted Answer · 2020-04-18 15:34:19Z

1

It merges this way because for lists += is an array concatenation and that in this context your string object is interpreted as an array of characters:

[] += "Hello"
# Equivalent to 
[] += ["H", "e", "l", "l", "o"]

If you want to join strings you can do:

out = "".join(array_test)

answered Apr 18, 2020 at 15:34

Louis Lac

6,5862 gold badges29 silver badges50 bronze badges

Comments

Patrick Artner · Accepted Answer · 2020-04-18 15:32:41Z

0

Your result becomes the way it is, because you take each inner string and add each character of it to your return-list without removing any spaces or commas.

You can change your code to:

def merge(strArr):
    new_list = []
    for inner in strArr:
        new_list.extend(inner.split(", "))  # split and extend instead of += (== append)

    return new_list


array_test =["1, 3, 4, 7, 13", "1, 2, 4, 13, 15"]
merged = merge(array_test)
as_int = list(map(int,merged))

print(merged)
print(as_int)

Output:

['1', '3', '4', '7', '13', '1', '2', '4', '13', '15']


[1, 3, 4, 7, 13, 1, 2, 4, 13, 15]

Without as_int()you will still hav strings in your list, you need to convert them into integers.

answered Apr 18, 2020 at 15:32

Patrick Artner

51.9k10 gold badges50 silver badges79 bronze badges

Collectives™ on Stack Overflow

Adding a string to an array adds all characters separately

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related