如何使用 if 语句检查我的日期？

Question

我在数据框中丢失了一些日期，我试图用前一个日期来填充它们。所以我想第一部分是检查是否holdings_df['date']在d. 希望你能帮助我，因为我被困住了。

这是我的功能

在：

def get_holdings_df_date(d):

    if (d in holdings_df['Date'].values):

        # return holdings_df.loc[holdings_df['Date'] == d]

        print('true')

print(get_holdings_df_date('2020-01-02'))

出去：

FutureWarning: elementwise comparison failed; returning scalar instead, but in the future will perform elementwise comparison

  if (d in holdings_df['Date'].values):

None

Traceback (most recent call last):

  File "calculatingnav.py", line 130, in <module>

    system.exit()

Answer 1

这看起来很简单。您的函数可能如下所示：def get_holdings_df_date(d):&nbsp; &nbsp; return True if str(d) in holdings_df["Date"].values else False整个代码示例：import pandas as pdtest = [&nbsp; &nbsp; ("2020-01-02", 34, "Sydney", 155),&nbsp; &nbsp; ("2020-01-03", 31, "Delhi", 177),&nbsp; &nbsp; ("2020-01-04", 16, "Mumbai", 81),&nbsp; &nbsp; ("2020-01-05", 31, "Delhi", 167),&nbsp; &nbsp; ("2020-01-06", 81, "Delhi", 144),&nbsp; &nbsp; ("2020-01-07", 35, "Mumbai", 135),&nbsp; &nbsp; ("2020-01-08", 35, "Colombo", 111),&nbsp; &nbsp; ("2020-01-09", 32, "Colombo", 111),]holdings_df = pd.DataFrame(test, columns=["Date", "x", "y", "z"])def get_holdings_df_date(d):&nbsp; &nbsp; return True if str(d) in holdings_df["Date"].values else Falseprint(get_holdings_df_date("2020-01-02"))输出：True