当列中已存在多种日期格式时，更改整个 Dataframe 列的日期格式？

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.这是我从 Excel 导入的关于各种沃尔玛债券到期日的数据列。 All I am concerned with is the year portion of these dates.我只关心这些日期的年份部分。 How can I format the entire column to just return the year values?如何格式化整个列以仅返回年份值？

dt.strftime didn't work dt.strftime 没有工作

Thanks in advance提前致谢

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.为您编写了这个小脚本，它应该 output 在 years.txt 文件中的年份，假设您的数据在 data.txt 中，就像您在上面发布的年份一样。

Script also lets you toggle if you want to include the dash and the years on the right.如果要在右侧包含破折号和年份，脚本还允许您切换。

Contents of the data.txt I tested with:我测试的data.txt的内容：

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:和我写的脚本：

#!/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:和output到years.txt：

Contact me if you have any issues, and I hope I can help you!有什么问题可以联系我，希望能帮到你！

当列中已存在多种日期格式时，更改整个 Dataframe 列的日期格式？

问题描述

1 个解决方案

解决方案1
0 2020-04-07 19:01:42

当列中已存在多种日期格式时，更改整个 Dataframe 列的日期格式？

问题描述

1 个解决方案

解决方案1 0 2020-04-07 19:01:42

解决方案1
0 2020-04-07 19:01:42