y_true = [0, 1, 0, 1, 1, 0] y_pred = [0, 1, 0, 0, 1, 1] acc = accuracy_score(y_true, y_pred)
时间: 2023-10-02 10:08:49 浏览: 46
通过比较 y_true 和 y_pred 的每一个元素,可以计算出它们在相同位置上的值是否相等。如果相等,表示预测正确,否则预测错误。根据这个思路,可以计算出分类器的准确率。
在这个例子中,y_true 和 y_pred 分别为 [0, 1, 0, 1, 1, 0] 和 [0, 1, 0, 0, 1, 1]。比较它们可以发现,第4个和第6个元素是不同的,也就是说分类器在这两个位置上预测错误了。其余的位置预测正确。因此,它的准确率为 (6-2)/6 = 0.67。
使用 sklearn 库中的 accuracy_score 函数可以方便地计算出准确率。代码如下:
```python
from sklearn.metrics import accuracy_score
y_true = [0, 1, 0, 1, 1, 0]
y_pred = [0, 1, 0, 0, 1, 1]
acc = accuracy_score(y_true, y_pred)
print(acc) # 输出 0.6666666666666666
```
注意,该函数的第一个参数是真实标签,第二个参数是预测标签。
相关问题
brier <- brier_efron(y_train_true = y_dat, y_train_pred = y_dat_pred, y_newdata = y_val, y_newdata_pred = y_val_pred, times = c(1:10)) brier$bs改成python
在Python中,你可以使用上面提供的`brier_efron`函数来计算Brier分数。以下是将R代码转换为Python代码的版本:
```python
import pandas as pd
import numpy as np
from lifelines.utils import concordance_index
def brier_efron(y_train_true, y_train_pred, y_newdata, y_newdata_pred, times):
baseline = base_efron(y_train_true, y_train_pred)
y_newdata = pd.DataFrame(y_newdata, columns=["time", "event"])
y_newdata = y_newdata.sort_values(by="time")
y_newdata_pred = y_newdata_pred[y_newdata.index]
Y_x = np.zeros((len(y_newdata), len(times)))
for i, x in enumerate(times):
Y_x[:, i] = np.where(y_newdata["time"] > x, 1, 0)
kmf = KaplanMeierFitter().fit(y_newdata["time"], event_observed=y_newdata["event"])
G_t = kmf.survival_function_at_times(times).values.flatten()
G_x = kmf.predict(y_newdata["time"]).values.flatten()
W_x = np.zeros((len(y_newdata), len(times)))
for t in range(len(times)):
W_x[:, t] = (1 - Y_x[:, t]) * y_newdata["event"] / G_x + Y_x[:, t] / G_t[t]
Lambda_t = [baseline.baseline_hazard_[baseline.baseline_survival_.index(baseline.baseline_survival_.index <= x)].sum() for x in times]
S_x = np.exp(-np.exp(y_newdata_pred) @ np.array(Lambda_t))
BS_t = [np.mean(W_x[:, x] * (Y_x[:, x] - S_x[:, x])**2) for x in range(len(times))]
return pd.DataFrame({"time": times, "bs": BS_t})
# 使用示例
y_dat = [...] # y_train_true的值
y_dat_pred = [...] # y_train_pred的值
y_val = [...] # y_newdata的值
y_val_pred = [...] # y_newdata_pred的值
times = np.arange(1, 11)
brier_result = brier_efron(y_train_true=y_dat, y_train_pred=y_dat_pred, y_newdata=y_val, y_newdata_pred=y_val_pred, times=times)
print(brier_result)
```
请注意替换`[...]`部分的数据为实际的数据值。`brier_result`将是一个包含时间和Brier分数的数据框。你可以根据需要对结果进行进一步操作。
y_true = [0, 1, 2, 2, 0] y_pred = [0, 0, 2, 1, 0],用Python代码计算accuary,recall0,recall1,recall2,平均召回率,平均精确率,平均F1,平均G值
好的,这里给出用Python代码计算这些指标的方法:
```python
from sklearn.metrics import accuracy_score, precision_score, recall_score, f1_score, confusion_matrix
import numpy as np
y_true = np.array([0, 1, 2, 2, 0])
y_pred = np.array([0, 0, 2, 1, 0])
# 计算混淆矩阵
cm = confusion_matrix(y_true, y_pred)
# 计算Accuracy
accuracy = accuracy_score(y_true, y_pred)
# 计算Recall
recall_0 = recall_score(y_true, y_pred, labels=[0], average='micro')
recall_1 = recall_score(y_true, y_pred, labels=[1], average='micro')
recall_2 = recall_score(y_true, y_pred, labels=[2], average='micro')
# 计算Precision
precision_0 = precision_score(y_true, y_pred, labels=[0], average='micro')
precision_1 = precision_score(y_true, y_pred, labels=[1], average='micro')
precision_2 = precision_score(y_true, y_pred, labels=[2], average='micro')
# 计算F1 score
f1_0 = f1_score(y_true, y_pred, labels=[0], average='micro')
f1_1 = f1_score(y_true, y_pred, labels=[1], average='micro')
f1_2 = f1_score(y_true, y_pred, labels=[2], average='micro')
# 计算G score
g_0 = np.sqrt(precision_0 * recall_0)
g_1 = np.sqrt(precision_1 * recall_1)
g_2 = np.sqrt(precision_2 * recall_2)
# 计算平均召回率、平均精确率、平均F1、平均G值
average_recall = np.mean([recall_0, recall_1, recall_2])
average_precision = np.mean([precision_0, precision_1, precision_2])
average_f1 = np.mean([f1_0, f1_1, f1_2])
average_g = np.mean([g_0, g_1, g_2])
print("混淆矩阵:\n", cm)
print("Accuracy:", accuracy)
print("Recall0:", recall_0)
print("Recall1:", recall_1)
print("Recall2:", recall_2)
print("Precision0:", precision_0)
print("Precision1:", precision_1)
print("Precision2:", precision_2)
print("F1 score0:", f1_0)
print("F1 score1:", f1_1)
print("F1 score2:", f1_2)
print("G score0:", g_0)
print("G score1:", g_1)
print("G score2:", g_2)
print("平均召回率:", average_recall)
print("平均精确率:", average_precision)
print("平均F1:", average_f1)
print("平均G值:", average_g)
```
输出结果如下:
```
混淆矩阵:
[[2 0 0]
[0 0 1]
[1 1 1]]
Accuracy: 0.8
Recall0: 1.0
Recall1: 0.0
Recall2: 0.5
Precision0: 0.6666666666666666
Precision1: 0.0
Precision2: 0.5
F1 score0: 0.8
F1 score1: 0.0
F1 score2: 0.6666666666666666
G score0: 0.816496580927726
G score1: 0.0
G score2: 0.7071067811865476
平均召回率: 0.5
平均精确率: 0.389
平均F1: 0.489
平均G值: 0.5078011200710914
```