CODEWITHSUNDEEP
pythonpython-3.xpandasdataframenumber-formatting
Tmiskiewicz
Tmiskiewicz

Reputation: 403

Adding value 0 to existing column based on comma

I have a DataFrame that looks like below:

name price
x    ,12
y    ,9
z    10,25

I have to add "0" before the comma (unless there is already a number before the comma, in that case it can't be changed) so DataFrame should looks like below:

name price
x    0,12
y    0,9
z    10,25

Do you have any ideas?

Upvotes: 0

Views: 42

Answers (2)

Serge de Gosson de Varennes
Serge de Gosson de Varennes

Reputation: 11502

EDIT Here is a potential solution:

    A   B
0   1   ,2
1   2   ,02
2   3   1,3
3   4   ,9
4   5   13
5   6   12

and

df['B'] = df['B'].str.replace(",", "0,",  regex=True)
df['B'] = df['B'].apply(lambda x: '{0:0>4}'.format(x))
df['B'] = df['B'].apply(lambda x: x.replace(',','.'))
df['B'] = df['B'].astype(float)

which gives

    A   B
0   1   0.20
1   2   0.02
2   3   1.30
3   4   0.90
4   5   13.00
5   6   12.00

Upvotes: 1

BenB
BenB

Reputation: 658

Assuming you are working with strings and not numbers, this does the trick for me:

df["price"] = df["price"].where(~df["price"].str.startswith(","), "0"+df["price"])

Here is an example

df = pd.DataFrame([["x",",12"],["y",",3"],["z","5"],["o","1,2"]], columns=["name","price"])
print("input:", df)
df["price"] = df["price"].where(~df["price"].str.startswith(","), "0"+df["price"])
print("output:", df)

yields:

input:   name price
0    x   ,12
1    y    ,3
2    z     5
3    o   1,2
output:   name price
0    x  0,12
1    y   0,3
2    z     5
3    o   1,2

Upvotes: 3

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