Python math operation on column

Question

Data from json is in df and am trying to ouput to a csv. I am trying to multiply dataframe column with a fixed value and having issues how data is displayed

I have used the following but the data is still not how i want to display

df_entry['Hours'] = df_entry['Hours'].multiply(2)
df_entry['Hours'] = df_entry['Hours'] * 2

Input

ID, name,hrs
100,AB,37.5

Expected

ID, name,hrs
100,AB,75.0

What I am getting

ID, name,hrs
100,AB,37.537.5

It appears "Hours" is a string column, so try converting it to numeric and multiplying using, `pd.to_numeric(df_entry['Hours'], errors='coerce') * 2` — cs95, May 31 '19 at 00:40

score 2 · Answer 1 · answered May 31 '19 at 00:40

2

That happens because the dtype of the column is str. You need to convert it to float before multiplication.

df_entry['Hours'] = df_entry['Hours'].astype(float) * 2

answered May 31 '19 at 00:40

foxpal

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jose_bacoy · Answer 2 · 2019-05-31T13:37:07.887

0

You can use apply function.

df_entry['Hours'] = df_entry['Hours'].apply(lambda x: float(int(x))*2)

edited May 31 '19 at 13:37

answered May 31 '19 at 00:37

jose_bacoy

12,227
1
20
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Thanks. I tried this and got the identical display as what i had earlier – Donnie May 31 '19 at 00:47
I updated my answer – jose_bacoy May 31 '19 at 13:37

Python math operation on column

2 Answers2