如何将numpy中的引号去掉

import io
from ast import literal_eval
import pandas as pd

data = """
y_train
[-2.6266341]
[1.4479955]
[-0.8753087]
[3.5259385]
[4.88593]
""".strip()

dtype_data = {'y_train': list}
df = pd.read_csv(io.StringIO(data), converters={'y_train': literal_eval})
values = df.values
print(values)

[[list([-2.6266341])]
 [list([1.4479955])]
 [list([-0.8753087])]
 [list([3.5259385])]
 [list([4.88593])]]

>>> values[0][0]
[-2.6266341]
>>> type(values[0][0])
<class 'list'>