ValueError：Series的真值是不明确的。使用a.empty，a.bool（），a.item（），a.any（）或a.all（）？

I'm noob with pandas, and recently, I got that 'ValueError' when I'm trying to modify the columns that follows some rules, as:

我是大熊猫的noob,最近,当我尝试修改遵循某些规则的列时,我得到了'ValueError',如:

csv_input = pd.read_csv(fn, error_bad_lines=False)
if csv_input['ip.src'] == '192.168.1.100':
        csv_input['flow_dir'] = 1  
        csv_input['ip.src'] = 1  
        csv_input['ip.dst'] = 0
    else:
        if csv_input['ip.dst'] == '192.168.1.100':
            csv_input['flow_dir'] = 0  
            csv_input['ip.src'] = 0
            csv_input['ip.dst'] = 1

I was searching about this error and I guess that it's because the 'if' statement and the '==' operator, but I don't know how to fix this.

我正在搜索这个错误,我想这是因为'if'语句和'=='运算符,但我不知道如何解决这个问题。

Thanks!

1 个解决方案

#1

So Andrew L's comment is correct, but I'm going to expand on it a bit for your benefit.

所以安德鲁的评论是正确的,但我会为了你的利益而扩展它。

When you call, e.g.

当你打电话时,例如

csv_input['ip.dst'] == '192.168.1.100'

What this returns is a Series, with the same index as csv_input, but all the values in that series are boolean, and represent whether the value in csv_input['ip.dst'] for that row is equal to '192.168.1.100'.

返回的是一个Series,其索引与csv_input相同,但该系列中的所有值都是boolean,并表示该行的csv_input ['ip.dst']中的值是否等于'192.168.1.100'。

So, when you call

所以,当你打电话的时候

 if csv_input['ip.dst'] == '192.168.1.100':

You're asking whether that Series evaluates to True or False. Hopefully that explains what it meant by The truth value of a Series is ambiguous., it's a Series, it can't be boiled down to a boolean.

你问这个系列是评估为True还是False。希望这能解释它的含义。系列的真值是模棱两可的。它是一个系列,它不能归结为布尔值。

Now, what it looks like you're trying to do is set the values in the flow_dir,ip.src & ip.dst columns, based on the value in the ip.src column.

现在,您尝试做的是根据ip.src列中的值设置flow_dir,ip.src和ip.dst列中的值。

The correct way to do this is would be with .loc[], something like this:

执行此操作的正确方法是.loc [],如下所示:

#equivalent to first if statement
csv_input.loc[
    csv_input['ip.src'] = '192.168.1.100',
    ('ip.src','ip.dst','flow_dir')
] = (1,0,1)

#equivalent to second if statement    
csv_input.loc[
    csv_input['ip.dst'] = '192.168.1.100',
    ('ip.src','ip.dst','flow_dir')
] = (0,1,0)

#1