Python Pandas concatenate strings and numbers into one string

Question

I am working with a pandas dataframe and trying to concatenate multiple string and numbers into one string.

This works

df1 = pd.DataFrame({'Col1': ['a', 'b', 'c'], 'Col2': ['a', 'b', 'c']})
df1.apply(lambda x: ', '.join(x), axis=1)

0    a, a
1    b, b
2    c, c

How can I make this work just like df1?

df2 = pd.DataFrame({'Col1': ['a', 'b', 1], 'Col2': ['a', 'b', 1]})
df2.apply(lambda x: ', '.join(x), axis=1)

TypeError: ('sequence item 0: expected str instance, int found', 'occurred at index 2')

try changing lambda x: ', '.join(x) to lambda x: ', '.join(str(x)) — dot.Py
– dot.Py, Commented May 24, 2017 at 20:18

piRSquared · Accepted Answer · 2017-05-24 20:26:35Z

5

Consider the dataframe df

np.random.seed([3,1415])
df = pd.DataFrame(
    np.random.randint(10, size=(3, 3)),
    columns=list('abc')
)

print(df)

   a  b  c
0  0  2  7
1  3  8  7
2  0  6  8

You can use astype(str) ahead of the lambda

df.astype(str).apply(', '.join, 1)

0    0, 2, 7
1    3, 8, 7
2    0, 6, 8
dtype: object

Using a comprehension

pd.Series([', '.join(l) for l in df.values.astype(str).tolist()], df.index)

0    0, 2, 7
1    3, 8, 7
2    0, 6, 8
dtype: object

answered May 24, 2017 at 20:26

piRSquared

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1 Comment

E.K. Over a year ago

This is great! Thank you

MaxU - stand with Ukraine · Accepted Answer · 2017-05-24 20:26:21Z

2

In [75]: df2
Out[75]:
  Col1 Col2 Col3
0    a    a    x
1    b    b    y
2    1    1    2

In [76]: df2.astype(str).add(', ').sum(1).str[:-2]
Out[76]:
0    a, a, x
1    b, b, y
2    1, 1, 2
dtype: object

answered May 24, 2017 at 20:26

MaxU - stand with Ukraine

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Comments

Sagar Waghmode · Accepted Answer · 2017-05-24 20:23:26Z

1

You have to convert column types to strings.

import pandas as pd
df2 = pd.DataFrame({'Col1': ['a', 'b', 1], 'Col2': ['a', 'b', 1]})
df2.apply(lambda x: ', '.join(x.astype('str')), axis=1)

answered May 24, 2017 at 20:23

Sagar Waghmode

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