在pandas DataFrame中的任何位置搜索值

这似乎是一个简单的问题，但是我之前找不到它（此和此很接近，但答案不好）。

This seems like a simple question, but I couldn't find it asked before (this and this are close but the answers aren't great).

问题是：如果我想在df中搜索某处的值（我不知道它在哪一列中），返回所有具有匹配项的行。

The question is: if I want to search for a value somewhere in my df (I don't know which column it's in) and return all rows with a match.

最古怪的方式是什么？还有什么比以下更好的东西了：

What's the most Pandaic way to do it? Is there anything better than:

for col in list(df):
    try:    
        df[col] == var
        return df[df[col] == var]
    except TypeError:
        continue 

？