系列的真实值是不明确的。无法弄清楚

我是python的新手...因此，我编写了此函数，该函数应规范数据框“价格”列中包含的价格值：

def normalize_price(df): 
    for elements in df['price']: 
        if (df["price"]>= 1000) and (df['price']<= 1499): 
            df['price'] = 1000 
            return
        elif 1500 <= df['price'] <= 2499:
            df['price'] = 1500 
            return
        elif 2500 <= df['price'] <= 2999:
            df['price'] = 2500 
            return
        elif 3000 <= df['price'] <= 3999:
            df['price'] = 3000 
            return

所以，当我称它为错误时

---------------------------------------------------------------------------
<ipython-input-86-1e239d3cbba4> in normalize_price(df)
     20 def normalize_price(df):
     21     for elements in df['price']:
---> 22         if (df["price"]>= 1000) and (df['price']<= 1499):
     23             df['price'] = 1000
     24             return

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

由于我快疯了，所以我想知道为什么:) 谢谢！