Changing pandas dataframe columns from int to string and saving as string csv

Question

I have a pandas dataframe which is initially columns of type int. I change the type to string and then save it using to_csv. But in the csv I am saving, I am not getting data in the form '1', '2',.., instead its like 1,2,...

This is what I am doing:

>>> import pandas as pd
>>> import numpy as np
>>> df = pd.DataFrame(np.random.randint(0,5,size=(3, 4)), columns=list('ABCD'))
>>> df
   A  B  C  D
0  2  3  0  4
1  4  0  3  4
2  4  4  4  3
>>> print(df.dtypes)
A    int64
B    int64
C    int64
D    int64
dtype: object
>>> df = df.astype(str)
>>> df
   A  B  C  D
0  2  3  0  4
1  4  0  3  4
2  4  4  4  3

>>> print(df.dtypes)
A    object
B    object
C    object
D    object
dtype: object
>>> df.to_csv('./df.csv', index = False)

When I check the saved file I get the following

➜ head -2 df.csv
A,B,C,D
2,3,0,4

I want it to be like the following:

➜ head -2 df.csv
A,B,C,D
"2","3","0","4"

You can just add the quoting param: df.to_csv('./df.csv', index=False, quoting=1) — Merelda
– Merelda, Commented Oct 21, 2019 at 14:51

Quang Hoang · Accepted Answer · 2019-10-21 14:54:41Z

1

You can pass quoting to to_csv:

import csv
df.to_csv('a.csv', index=False,, quoting=csv.QUOTE_NONNUMERIC)

# or without importing csv module
df.to_csv('a.csv', index=False,, quoting=2)

You can even do with the original data frame with quoting=1:

df.to_csv('a.csv' quoting=1)

Output:

"A","B","C","D"
"2","3","0","4"
"4","0","3","4"
"4","4","4","3"

answered Oct 21, 2019 at 14:54

Quang Hoang

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Comments

cloud88111 · Accepted Answer · 2019-10-21 14:51:00Z

0

This works

df = df.apply(lambda x: '"' + str(x) + '"')

answered Oct 21, 2019 at 14:51

cloud88111

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