Python：如何计算当前年份和列中年份之间的差异？

我有一个列“DateBecameRep_Year”，其中只包含年份值（即1974年、1999年等）。我想在我的数据框中创建一个新列，用于计算当前年份与“DateBecameRep_year”字段中年份之间的差异

下面是我尝试使用的代码：

df_DD['DateBecameRep_Year'] = pd.to_datetime(df_DD['DateBecameRep_Year'])

df_DD['Current Year'] = datetime.now().year
df_DD['Current Year'] = pd.to_datetime(df_DD['Current Year'])

df_DD['Years_Since_BecameRep'] = df_DD['Current Year'] - df_DD['DateBecameRep_Year']  
df_DD['Years_Since_BecameRep'] = df_DD['Years_Since_BecameRep'] / np.timedelta64(1, 'Y')

df_DD['Years_Since_BecameRep'].head()

这是我得到的输出，看起来很奇怪：

我的假设是，这与以下因素有关：

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非常感谢您的帮助

如果您只想得到不同的年份号，只需使用减法，无需转换为日期时间

import pandas as pd
import datetime
current_year = datetime.datetime.now().year #get current year
df_DD = pd.DataFrame.from_dict({"DateBecameRep_Year":[1999,2000,2015,1898,1788,1854]})
df_DD['Current Year'] = datetime.datetime.now().year
df_DD["Years_Since_BecameRep"] = df_DD['Current Year'] - df_DD['DateBecameRep_Year']  # substract to get the year delta

df_DD

将：

    DateBecameRep_Year  Current Year    Years_Since_BecameRep
0   1999                2017            18
1   2000                2017            17
2   2015                2017            2
3   1898                2017            119
4   1788                2017            229
5   1854                2017            163

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你能用一个小的可复制数据集（文本/CSV格式）和所需的数据集来扩展你的问题吗？现在很清楚你想要实现什么。。。为什么要将年份（整数）转换为

datetime

dtype？我想您需要的只是年份之间的差异？如果是这样，请从代码中删除第三行。将所有代码替换为

df_DD['Years\u Since\u BecameRep']=datetime.now（）.year-df_DD['DateBecameRep\u year']

仅此而已，否？是的，您是对的。。。我应该把df_DD['DateBecameRep_Year']作为一个浮点数，然后减去——谢谢@我想你只需要：

df\u DD['Years\u Since\u BecameRep']=pd.datetime.now（）.year-df\u DD['DateBecameRep\u year']