Keras - ValueError：无法将字符串转换为浮点数答案

【问题标题】：Keras - ValueError: could not convert string to floatKeras - ValueError：无法将字符串转换为浮点数
【发布时间】：2019-06-19 14:40:48
【问题描述】：

我有如下所示的代码，但得到以下错误：

ValueError：无法将字符串转换为浮点数：BRAF

假设这是我的数据样本（| 只是我在此处添加的用于演示的分隔符，您可以想象每个值在 CSV 文件的单独单元格中）：

c.401C>T |皮肤| 23:141905805-141905805 | 9947 | BRAF

字符串可能是问题吗？在这种情况下如何读取和传递字符串？

from keras.models import Sequential
from keras.layers import Dense
from keras.models import Sequential, load_model
from keras.layers import Dense, Dropout, BatchNormalization, Activation
from keras.wrappers.scikit_learn import KerasRegressor

from sklearn.cross_validation import train_test_split
import pandas as pd
import numpy as np

df1 = pd.read_csv('mutation-train.csv')
y = df1[['Histology']]
X = df1[["CDS_Mutation","Primary_Tissue","Genomic","Gene_ID","Official_Symbol"]]

X = X.astype(np.str).values
y = y.astype(np.str).values

df2 = pd.read_csv('mutation-test.csv')

X_Test = df2[["CDS_Mutation","Primary_Tissue","Genomic","Gene_ID","Official_Symbol"]]
X_Test = X_Test.astype(np.str).values

X_train, X_test, y_train, y_test = train_test_split(X, y, train_size=0.2)

seed = 42
np.random.seed(seed)

model = Sequential()
#input layer
model.add(Dense(8, input_shape=(5,)))
model.add(BatchNormalization())
model.add(Activation("relu"))
model.add(Dropout(0.4))

model.add(Dense(8))
model.add(BatchNormalization())
model.add(Activation("sigmoid"))
model.add(Dropout(0.4))

model.add(Dense(4))
model.add(BatchNormalization())
model.add(Activation("sigmoid"))
model.add(Dropout(0.4))

model.add(Dense(2, activation="sigmoid"))

model.add(Dense(1, activation='linear'))

model.compile(loss='binary_crossentropy', optimizer='adam', metrics=['accuracy'])

model.fit(X, y, nb_epoch=300, batch_size=30)

谢谢。

编辑

这是回溯：

File "my_code.py", line 16, in <module>
    df1 = pd.read_csv('mutation-train.csv',header=None,names=headers, dtype=dtypes)
  File "/Users/abder/anaconda2/lib/python2.7/site-packages/pandas/io/parsers.py", line 678, in parser_f
    return _read(filepath_or_buffer, kwds)
  File "/Users/abder/anaconda2/lib/python2.7/site-packages/pandas/io/parsers.py", line 446, in _read
    data = parser.read(nrows)
  File "/Users/abder/anaconda2/lib/python2.7/site-packages/pandas/io/parsers.py", line 1036, in read
    ret = self._engine.read(nrows)
  File "/Users/abder/anaconda2/lib/python2.7/site-packages/pandas/io/parsers.py", line 1848, in read
    data = self._reader.read(nrows)
  File "pandas/_libs/parsers.pyx", line 876, in pandas._libs.parsers.TextReader.read
  File "pandas/_libs/parsers.pyx", line 891, in pandas._libs.parsers.TextReader._read_low_memory
  File "pandas/_libs/parsers.pyx", line 968, in pandas._libs.parsers.TextReader._read_rows
  File "pandas/_libs/parsers.pyx", line 1094, in pandas._libs.parsers.TextReader._convert_column_data
  File "pandas/_libs/parsers.pyx", line 1162, in pandas._libs.parsers.TextReader._convert_tokens

【问题讨论】：

请分享完整的 Traceback 错误
试试float('BRAF')。从您的代码中不清楚并且缺少回溯的是，谁在尝试将此字符串转换为浮点数。
感谢您的友好回复。当然，请在上面找到我的编辑以获取回溯。

标签： python pandas csv numpy keras

【解决方案1】：

如果你的 csv ('BRAF') 的最后一个值是分类的，你可以使用 keras to_categorical 方法使用 one-hot 向量对其进行编码，这是神经网络的推荐编码。 p>

from keras.utils import to_categorical

# one hot encode
encoded = to_categorical(data)
print(encoded)

Encoding Categorical Features Keras Docs - to_categorical

【讨论】：