pandas “类型错误：单例数组不能被视为有效集合”使用 sklearn train_test_split
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"TypeError: Singleton array cannot be considered a valid collection" using sklearn train_test_split
提问by John Samuel
TypeError: Singleton array array(0.2) cannot be considered a valid collection.
类型错误：单例数组 array(0.2) 不能被视为有效集合。
X = df.iloc[:, [1,7]].values
y= df.iloc[:,-1].values
from sklearn.model_selection import train_test_split
X_train, X_test, y_train, y_test = train_test_split(X, y, 0.2)
I am getting this error when trying to train_test_split. I am able to train my model with X and y values. However, i would like to split my dataframe and then train and test it.
尝试 train_test_split 时出现此错误。我能够用 X 和 y 值训练我的模型。但是，我想拆分我的数据帧，然后对其进行训练和测试。
Any help is appreciated.
任何帮助表示赞赏。
回答by cs95
A not-so-commonly known fact is that train_test_splitcan split any number of arrays, not just two ("train", and "test"). See the linked docs and the source codefor more info.
一个鲜为人知的事实是，它train_test_split可以拆分任意数量的数组，而不仅仅是两个（“train”和“test”）。有关更多信息，请参阅链接的文档和源代码。
For example,
例如，
np.random.seed(0)
df1 = pd.DataFrame(np.random.choice(10, (5, 4)), columns=list('ABCD'))
y = df1.pop('C')
z = df1.pop('D')
X = df1
splits = train_test_split(X, y, z, test_size=0.2)
len(splits)
# 6
IOW, the only way to specify the test size is by specifying the keyword argument test_size. All positional arguments are assumed to be collections that are to be split, and in your case, since you do
IOW，指定测试大小的唯一方法是指定关键字参数test_size。假定所有位置参数都是要拆分的集合，在您的情况下，因为您这样做
train_test_split(X, y, 0.2)
The function tries to split 0.2, but since a float is not a collection, the error is raised. The solution is to (as mentioned), specify the keyword argument:
该函数尝试 split 0.2，但由于 float 不是集合，因此会引发错误。解决方案是（如前所述）指定关键字参数：
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2)
