Split strings in tuples into columns, in Pandas

Question

I have the following DataFrame, where Track ID is the row index. How can I split the string in the stats column into 5 columns of numb

Answer 1

Assuming you have a column which contains tuples (as it appears in your example) rather than strings, this will work:

df = pandas.DataFrame({'Track ID': [14, 28, 42], 'stats': [(1, 2, 3, 4, 5), (1, 2, 3, 4, 5), (1, 2, 3, 4, 5)]}).set_index("Track ID")

from operator import itemgetter
for i in range(5):
    df["Col {}".format(i)] = df.stats.apply(itemgetter(i))

If you actually have strings that look like tuples, you can parse them first and then apply the same pattern as above:

df = df2 = pandas.DataFrame({'Track ID': [14, 28, 42], 'stats': ["(1, 2, 3, 4, 5)", "(1, 2, 3, 4, 5)", "(1, 2, 3, 4, 5)"]}).set_index("Track ID")
df.stats = df2.stats.str.strip("()").str.split(", ")

Answer 2

If you have a sequence of tuples and not strings, and you want them as DataFrame columns, this is the simplest approach:

df = pd.concat([df['Track ID'],pd.DataFrame(df['stats'].values.tolist())], axis=1)

If it is actually strings, you can first convert it to lists like so, then apply the above operation:

dfpart = pd.DataFrame(df['stats'].apply(lambda x: x.strip('()').split(', ')).values.tolist()).astype(float)
df = pd.concat([df['Track ID'], dfpart], axis=1)

Answer 3

And for the other case, assuming it are strings that look like tuples:

In [74]: df['stats'].str[1:-1].str.split(',', expand=True).astype(float)
Out[74]:
          0         1         2         3         4
0 -0.009242  0.410000 -0.742016  0.003683  0.002517
1  0.041154  0.318231  0.758717  0.002640  0.010654
2 -0.014435  0.168438 -0.808703  0.000817  0.003166
3  0.034346  0.288731  0.950845  0.000001  0.003373
4  0.009052  0.151031  0.670257  0.012179  0.003022
5 -0.004797  0.171615 -0.552879  0.050032  0.002180

(note: for older versions of pandas (< 0.16.1), you need to use return_type='frame' instead of the expand keyword)

By the way, if it are tuples and not strings, you can simply do the following:

pd.DataFrame(df['stats'].tolist(), index=df.index)