如何删除行，如果列对它有类似的值对?

Question

我有一个数据框架:

val1      val2
"a"       "b"
"b"       "a"
"c"        "m"
"c"        "m"
"m"        "c"

如果两列在同一行上包含两个相似的值，则必须删除该行。所以期望的结果是:

val1      val2
"a"       "b"
"c"        "m"

我怎么能那样做呢?

Answer 1

您可以使用布尔索引与agg/duplicated:

# is the pair val1/var2 duplicated ?
m = df.agg(lambda x: sorted(list(x)), axis=1).duplicated(keep="first")
​
out = df.loc[~m]

输出:

print(out)
val1 val2
0  "a"  "b"
2  "c"  "m"