请教dataframe遍历与字符串匹配问题

dataframe：936 rows × 3 columns
index全是文本，有些单元格是重复的
如何找出前列两中与第三列重复的内容呢？

可用索引引用。示例如下：

import pandas as pd 

data={'fruits':['apple','banana','pear','grape'],'animals':['cat','dog','fox','monkey'],'category':['pineapple','apple','cat','monkey']}
df=pd.DataFrame(data,index=['a','b','c','d'])
#print(df)
#if (df['fruits']==df[category]) or (df['animals']==df['category'])
res=df[(df['fruits']==df['category']) | (df['animals']==df['category'])]#不遍历获取
print(res)
for i in df.index:
    if df['fruits'][i] == df['category'][i] or df['animals'][i] == df['category'][i]:#完全匹配用==，部分匹配用in
        print(df.loc[i,:].to_frame())

发出来看看