Changing the date format of an entire Dataframe column when multiple date formats already exist in the column?

Question

bond_df['Maturity']

0     2022-07-15 00:00:00
1     2024-07-18 00:00:00
2     2027-07-16 00:00:00
3     2020-07-28 00:00:00
4     2019-10-09 00:00:00
5     2022-04-08 00:00:00
6     2020-12-15 00:00:00
7     2022-12-15 00:00:00
8     2026-04-08 00:00:00
9     2023-04-11 00:00:00
10    2024-12-15 00:00:00
11                   2019
12    2020-10-25 00:00:00
13    2024-04-22 00:00:00
14    2047-12-15 00:00:00
15    2020-07-08 00:00:00
17    2043-04-11 00:00:00
18                   2021
19                   2022
20                   2023
21                   2025
22                   2026
23                   2027
24                   2029
25    2021-04-15 00:00:00
26    2044-04-22 00:00:00
27    2043-10-02 00:00:00
28    2039-01-19 00:00:00
29    2040-07-09 00:00:00
30    2029-09-21 00:00:00
31    2040-10-25 00:00:00
32                   2019
33    2035-09-04 00:00:00
34    2035-09-28 00:00:00
35    2041-04-15 00:00:00
36    2040-04-02 00:00:00
37    2034-03-27 00:00:00
38                   2030
39    2027-04-05 00:00:00
40    2038-04-15 00:00:00
41    2037-08-17 00:00:00
42    2023-10-16 00:00:00
43                      -
45    2019-10-09 00:00:00
46                      -
47    2021-06-23 00:00:00
48    2021-06-23 00:00:00
49    2023-06-26 00:00:00
50    2025-06-26 00:00:00
51    2028-06-26 00:00:00
52    2038-06-28 00:00:00
53    2020-06-23 00:00:00
54    2020-06-23 00:00:00
55    2048-06-29 00:00:00
56                      -
57                      -
58    2029-07-08 00:00:00
59    2026-07-08 00:00:00
60    2024-07-08 00:00:00
61    2020-07-31 00:00:00
Name: Maturity, dtype: object

This is a column of data that I imported from Excel of maturity dates for various Walmart bonds. All I am concerned with is the year portion of these dates. How can I format the entire column to just return the year values?

dt.strftime didn't work

Thanks in advance

Answer 1

Wrote this little script for you which should output the years in a years.txt file, assuming your data is in data.txt as only the years you posted above.

Script also lets you toggle if you want to include the dash and the years on the right.

Contents of the data.txt I tested with:

0     2022-07-15 00:00:00
1     2024-07-18 00:00:00
2     2027-07-16 00:00:00
3     2020-07-28 00:00:00
4     2019-10-09 00:00:00
5     2022-04-08 00:00:00
6     2020-12-15 00:00:00
7     2022-12-15 00:00:00
8     2026-04-08 00:00:00
9     2023-04-11 00:00:00
10    2024-12-15 00:00:00
11                   2019
12    2020-10-25 00:00:00
13    2024-04-22 00:00:00
14    2047-12-15 00:00:00
15    2020-07-08 00:00:00
17    2043-04-11 00:00:00
18                   2021
19                   2022
20                   2023
21                   2025
22                   2026
23                   2027
24                   2029
25    2021-04-15 00:00:00
26    2044-04-22 00:00:00
27    2043-10-02 00:00:00
28    2039-01-19 00:00:00
29    2040-07-09 00:00:00
30    2029-09-21 00:00:00
31    2040-10-25 00:00:00
32                   2019
33    2035-09-04 00:00:00
34    2035-09-28 00:00:00
35    2041-04-15 00:00:00
36    2040-04-02 00:00:00
37    2034-03-27 00:00:00
38                   2030
39    2027-04-05 00:00:00
40    2038-04-15 00:00:00
41    2037-08-17 00:00:00
42    2023-10-16 00:00:00
43                      -
45    2019-10-09 00:00:00
46                      -
47    2021-06-23 00:00:00
48    2021-06-23 00:00:00
49    2023-06-26 00:00:00
50    2025-06-26 00:00:00
51    2028-06-26 00:00:00
52    2038-06-28 00:00:00
53    2020-06-23 00:00:00
54    2020-06-23 00:00:00
55    2048-06-29 00:00:00
56                      -
57                      -
58    2029-07-08 00:00:00
59    2026-07-08 00:00:00
60    2024-07-08 00:00:00
61    2020-07-31 00:00:00

and the script I wrote:

#!/usr/bin/python3
all_years = []
include_dash = False
include_years_on_right = True
with open("data.txt", "r") as f:
    text = f.read()
    lines = text.split("\n")

for line in lines:
    line = line.strip()
    if line == "":
        continue
    if "00" in line:
        all_years.append(line.split("-")[0].split()[-1])
    else:
        if include_years_on_right == False:
            continue
        year = line.split(" ")[-1]
        if year == "-":
            if include_dash == True:
                all_years.append(year)
            else:
                continue
        else:
            all_years.append(year)
with open("years.txt", "w") as f:
    for year in all_years:
        f.write(year + "\n")

and the output to the years.txt:

Contact me if you have any issues, and I hope I can help you!

Changing the date format of an entire Dataframe column when multiple date formats already exist in the column?

Question

1 answers

solution1
0 2020-04-07 19:01:42

Changing the date format of an entire Dataframe column when multiple date formats already exist in the column?

Question

1 answers

solution1 0 2020-04-07 19:01:42

solution1
0 2020-04-07 19:01:42