python - 比较数据帧后，输出 CSV 未返回所有行

Question

我找到了一个可以比较两个数据帧的函数。在使用时，它似乎正确地比较了它们并且它使用的是外部连接，但是当它应该是 180 行时输出只有 40 行。更奇怪的是索引行索引仍然存在。它从第 0 行开始，然后跳到第 140 行。

我还尝试打印输出以检查“to_csv”函数期间是否存在错误，并且它输出相同的内容。

功能:

def df_difference(df1, df2, which=None):
    # Find rows which are different between two DataFrames.
    comparison_df = df1.merge(df2,
                              indicator=True,
                              how='outer')
    if which is None:
        diff_df = comparison_df[comparison_df['_merge'] != 'both']
    else:
        diff_df = comparison_df[comparison_df['_merge'] == which]
    diff_df.to_csv('data/diff ' + now.strftime('%m-%d-%Y') + '.csv')
    return diff_df

函数的使用:

df_compared = df_difference(df_check[['SS', 'F_DOD']], df_to_add_pc[['SS', 'F_DOD']])

当前输出:

,    SS,       EnteredDate,  F_DOD       ,_merge
0,   12,      2020-06-18    ,2020-06-01  ,left_only
140, 123,,    2020-05-19                 ,right_only
141, 1234,,   2020-06-06                 ,right_only
142, 12345,,  2020-06-06                 ,right_only
143, 123456,, 2020-05-02                 ,right_only
144, 11234,,  2020-05-23                 ,right_only
145, 22134,,  2020-05-29                 ,right_only
146, 123124,, 2020-05-22                 ,right_only
147, 1234512,,2020-05-28                 ,right_only
148, 521312,, 2020-05-17                 ,right_only
149, 123412,, 2020-05-26                 ,right_only
150, 1236231,,2020-05-25                 ,right_only
151, 782123,, 2020-05-27                 ,right_only
152, 7812312,,2020-05-17                 ,right_only
153, 879122,, 2020-05-10                 ,right_only
154, 981293,, 2020-06-05                 ,right_only
155, 98712,,  2020-05-15                 ,right_only
156, 867891,, 2020-05-11                 ,right_only
157, 12312,,  2020-05-13                 ,right_only
158, 123541,, 2020-05-29                 ,right_only
159, 98712,,  2020-05-09                 ,right_only
160, 908123,, 2020-06-04                 ,right_only
161, 897291,, 2020-06-04                 ,right_only
162, 8791231,,2020-06-01                 ,right_only
163, 89712,,  2020-05-12                 ,right_only
164, 9081,,   2020-05-17                 ,right_only
165, 98712,,  2020-05-30                 ,right_only
166, 0123,,   2020-06-06                 ,right_only
167, 8213,,   2020-05-22                 ,right_only
168, 9891,,   2020-05-19                 ,right_only
169, 90812,,  2020-05-24                 ,right_only
170, 908122,, 2020-06-01                 ,right_only
171, 52131,,  2020-05-23                 ,right_only
172, 34512,,  2020-05-09                 ,right_only
173, 987891,, 2020-04-19                 ,right_only
174, 908102,, 2020-05-05                 ,right_only
175, 09521,,  2020-05-08                 ,right_only
176, 82134,,  2020-05-16                 ,right_only
177, 87182,,  2020-05-10                 ,right_only
178, 76812,,  2020-05-28                 ,right_only
179, 78921,,  2020-04-18                 ,right_only
180, 89612,,  2020-04-17                 ,right_only
181, 786123,, 2019-10-04                 ,right_only

预期输出:寻找与当前输出相同的格式，但包括缺少的 100 多行。

Answer 1

为了查看整个输出，只需返回合并后的输出而不进行过滤:

def df_difference(df1, df2, which=None):
    # Find rows which are different between two DataFrames.
    comparison_df = df1.merge(df2,indicator=True,how='outer')
    return comparison_df