I'm trying to read a CSV file to a pandas dataframe. The file has dates as 4 digit numbers (e.g., 2001, 2002). Is there a way to convert the 4 digit year to a full year-end format date (12/31/2001) via the parse_date in read_csv?

CodePudding user response：

I had a problem like that and solve like this:

I had a variable called my_year

date = ('12'  "/"   '31'  "/"   my_year)

It worked for me

CodePudding user response：

You can use apply and give either a function or a lambda function

Dummy data:

df = pd.DataFrame([2020 for _ in range(20)], columns=["year"])
df

Output:

    year
0   2020
1   2020
2   2020
3   2020
4   2020
5   2020
6   2020
7   2020
8   2020
9   2020
10  2020
11  2020
12  2020
13  2020
14  2020
15  2020
16  2020
17  2020
18  2020
19  2020

apply

Here we apply a string concatenation using fstring:

df["year"] = df["year"].apply(lambda row: f'12/31/{row}')
df

Output:

          year
0   12/31/2020
1   12/31/2020
2   12/31/2020
3   12/31/2020
4   12/31/2020
5   12/31/2020
6   12/31/2020
7   12/31/2020
8   12/31/2020
9   12/31/2020
10  12/31/2020
11  12/31/2020
12  12/31/2020
13  12/31/2020
14  12/31/2020
15  12/31/2020
16  12/31/2020
17  12/31/2020
18  12/31/2020
19  12/31/2020