python - 产生错误时中断for循环Python

Question

我希望我的Python循环(如下所示)能够正常工作，直到产生错误为止。我在其他地方看到过可以在for循环内使用while True，但不确定是否可以将其与错误链接。产生的错误可能与此类似:

ValueError: No neighbors found for test samples [700], you can try using larger radius, give a label for outliers, or consider removing them from your dataset.

如何将其合并到循环中？

x = 0
y = 0

for i in range(100):
    raidus_class = RadiusNeighborsClassifier(radius=100-i).fit(X_train, y_train)

    new["radius"] = raidus_class.predict(X_test)

    if (sum(new.quality == new.radius) > x):
        x = sum(new.quality == new.radius)
        y = i
    print(i)

print("Sum of correct prediction: ", x)
print("At n-neighbours = ", y)

非常感谢，本。

Answer 1

可以使用Python中的异常来完成

请注意，以下代码仅在遇到ValueError时停止

x = 0
y = 0

for i in range(100):
    try:
        raidus_class = RadiusNeighborsClassifier(radius=100-i).fit(X_train, y_train)

        new["radius"] = raidus_class.predict(X_test)

        if (sum(new.quality == new.radius) > x):
            x = sum(new.quality == new.radius)
            y = i
        print(i)
    except ValueError:
        break

print("Sum of correct prediction: ", x)
print("At n-neighbours = ", y)

我们可以使用捕获任何类型的异常

x = 0
y = 0

for i in range(100):
    try:
        raidus_class = RadiusNeighborsClassifier(radius=100-i).fit(X_train, y_train)

        new["radius"] = raidus_class.predict(X_test)

        if (sum(new.quality == new.radius) > x):
            x = sum(new.quality == new.radius)
            y = i
        print(i)
    except:
        break

print("Sum of correct prediction: ", x)
print("At n-neighbours = ", y)

警告!特别是在使用jupyter时，使用异常将忽略中断或停止，但是这不应该成为问题，因为语句中已包含中断。