Pandas: How to workaround “error tokenizing data”?

Question

A lot of questions have been already asked about this topic on SO. (and many others). Among the numerous answers, none of them was really helpful to me so far. If I missed

Answer 1

I have a different take on the solution. Let pandas take care of creating the table and deleting None values and let us take care of writing a proper tokenizer.

Tokenizer

def tokenize(str):
    idx = [x for x, v in enumerate(str) if v == '\"']
    if len(idx) % 2 != 0:
        idx = idx[:-1]
    memory = {}
    for i in range(0, len(idx), 2):
        val = str[idx[i]:idx[i+1]+1]
        key = "_"*(len(val)-1)+"{0}".format(i)
        memory[key] = val
        str = str.replace(memory[key], key, 1)        
    return [memory.get(token, token) for token in str.split(",")]  

Test cases for Tokenizer

print (tokenize("1,2,3,4,5"))
print (tokenize(",,3,\"Hello, World!\",5,6"))
print (tokenize(",,3,\"Hello,,,, World!\",5,6"))
print (tokenize(",,3,\"Hello, World!\",5,6,,3,\"Hello, World!\",5,6"))
print (tokenize(",,3,\"Hello, World!\",5,6,,3,\"Hello,,5,6"))

Output

['1', '2', '3', '4', '5'] ['', '', '3', '"Hello, World!"', '5', '6'] ['', '', '3', '"Hello,,,, World!"', '5', '6'] ['', '', '3', '"Hello, World!"', '5', '6', '', '3', '"Hello, World!"', '5', '6'] ['', '', '3', '"Hello, World!"', '5', '6', '', '3', '"Hello', '', '5', '6']

Putting the tokenizer into action

with open("test1.csv", "r") as fp:
    lines = fp.readlines()

lines = list(map(lambda x: tokenize(x.strip()), lines))
df = pd.DataFrame(lines).replace(np.nan, '')

Advantage:

Now we can teak the tokenizer function as per our needs