在大 pandas 的列中获取具有相同值的行 [英] Get rows that have the same value across its columns in pandas

问题描述

在大熊猫中，给出一个DataFrame D：

  + ----- + -------- + -------- + -------- + 
 | | 1 | 2 | 3 | 
 + ----- + -------- + -------- + -------- + 
 | 0 |苹果|香蕉|香蕉| 
 | 1 |橙色|橙色|橙色| 
 | 2 |香蕉|苹果|橙色| 
 | 3 | NaN | NaN | NaN | 
 | 4 |苹果|苹果|苹果| 
 + ----- + -------- + -------- + -------- + 
  

如果有三列或更多列返回此列，那么如何返回其所有列中具有相同内容的行？

  + ----- + -------- + -------- + ------ -  + 
 | | 1 | 2 | 3 | 
 + ----- + -------- + -------- + -------- + 
 | 1 |橙色|橙色|橙色| 
 | 4 |苹果|苹果|苹果| 
 + ----- + -------- + -------- + -------- + 
  

注意，当所有值都是NaN时，它会跳过行。

如果这只是两列，我通常做 D [D [1] == D [2]] 但是我不知道如何推广超过2列DataFrames。

解决方案

类似于Andy Hayden回答，检查如果min等于max（然后行元素都是重复的）：

  df [df.apply（lambda x：min（x）== max（x），1）] 
  

In pandas, given a DataFrame D:

+-----+--------+--------+--------+   
|     |    1   |    2   |    3   |
+-----+--------+--------+--------+
|  0  | apple  | banana | banana |
|  1  | orange | orange | orange |
|  2  | banana | apple  | orange |
|  3  | NaN    | NaN    | NaN    |
|  4  | apple  | apple  | apple  |
+-----+--------+--------+--------+

How do I return rows that have the same contents across all of its columns when there are three columns or more such that it returns this:

+-----+--------+--------+--------+   
|     |    1   |    2   |    3   |
+-----+--------+--------+--------+
|  1  | orange | orange | orange |
|  4  | apple  | apple  | apple  |
+-----+--------+--------+--------+

Note that it skips rows when all values are NaN.

If this were only two columns, I usually do D[D[1]==D[2]] but I don't know how to generalize this for more than 2 column DataFrames.

解决方案

Similar to Andy Hayden answer with check if min equal to max (then row elements are all duplicates):

df[df.apply(lambda x: min(x) == max(x), 1)]

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