Pandas loc 错误：“系列”对象是可变的，因此它们不能被散列

Question

Hey guys i need some help with a Problem in handling Panda dataframes. Here is the Code:

df.drop(df.index[0], inplace=True)
df.columns = ['Mic. No.', 'X', 'Y', 'Z', 'Re. Pre.', 'Im. Pre.']
df['Pre'] = df['Re. Pre.'] + df['Im. Pre.'] * 1j
df.drop(['Mic. No.', 'Re. Pre.', 'Im. Pre.'], axis=1, inplace=True)

if z != 0:
   df = df.loc(df['Z'] == z)

i loaded an excel sheet in a panda dataframe. Now after some preprocessing the dataframe is in the following form:

          X         Y     Z                       Pre
  1      0.16      0.16  0.05   (1.0048704-0.51310315j)
  2      0.16     -0.16  0.05   (0.24814222-1.6094971j)
  3     -0.16      0.16  0.05   (0.24815122-1.6094059j)
  4     -0.16     -0.16  0.05   (1.0048704-0.51310315j)
  5 -0.154993  0.154993  0.05  (-0.13939651-1.7231593j)

now i want to delete all columns in the dataframe witch dont have the Value z in the column "Z". I get the error: "TypeError:'Series' objects are mutable, thus they cannot be hashed". I dont know what to do because how i see it its exacly the same like in the pandas documentary.https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.DataFrame.loc.html :

df.loc[df['shield'] > 6]
               max_speed  shield
 sidewinder          7       8

please i need your help.

Thanks ahead!

Answer 1

你也可以用 lambda 表达式来做到这一点：

df = df[lambda x: x['Z'] == z]

Answer 2

您可以在df.loc使用方括号：

df = df.loc[df['Z'] == z]