Question

有人可以告诉我为什么会收到此错误？

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <groupId>Group</groupId>
    <artifactId>Parent</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <java.source-target.version>1.8</java.source-target.version>
        <aspectj.version>1.8.2</aspectj.version>
    </properties>

    <build>
        <pluginManagement>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.6.1</version>
                    <configuration>
                        <source>${java.source-target.version}</source>
                        <target>${java.source-target.version}</target>
                        <useIncrementalCompilation>false</useIncrementalCompilation>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-antrun-plugin</artifactId>
                    <executions>
                        <execution>
                            <id>createClassesDir</id>
                            <phase>process-resources</phase>
                            <configuration>
                                <tasks>
                                    <mkdir dir="${project.build.directory}\unwoven-classes" />
                                    <mkdir dir="${project.build.directory}\classes" />
                                </tasks>
                            </configuration>
                            <goals>
                                <goal>run</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
                <plugin>
                    <groupId>org.codehaus.mojo</groupId>
                    <artifactId>aspectj-maven-plugin</artifactId>
                    <version>1.7</version>
                    <configuration>
                        <complianceLevel>1.8</complianceLevel>
                        <source>${aspectj.version>}</source>
                        <target>${aspectj.version>}</target>
                        <weaveDirectories>
                            <weaveDirectory>${project.build.directory}\unwoven-classes</weaveDirectory>
                        </weaveDirectories>
                    </configuration>
                    <executions>
                        <execution>
                            <phase>process-classes</phase>
                            <goals>
                                <goal>compile</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
                <plugin>
                    <groupId>net.alchim31.maven</groupId>
                    <artifactId>scala-maven-plugin</artifactId>
                    <executions>
                        <execution>
                            <id>scala-compile-first</id>
                            <phase>process-resources</phase>
                            <goals>
                                <goal>add-source</goal>
                                <goal>compile</goal>
                            </goals>
                        </execution>
                        <execution>
                            <id>scala-test-compile</id>
                            <phase>process-test-resources</phase>
                            <goals>
                                <goal>testCompile</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
            </plugins>
        </pluginManagement>
    </build>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.aspectj</groupId>
                <artifactId>aspectjrt</artifactId>
                <version>${aspectj.version}</version>
                <scope>runtime</scope>
            </dependency>
            <dependency>
                <groupId>org.scala-lang</groupId>
                <artifactId>scala-library</artifactId>
                <version>2.12.1</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>4.12</version>
                <scope>test</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <modules>
        <module>Aspects</module>
    </modules>
</project>

我是新手编码，所以需要一些帮助：）

我的代码如下所示：

Traceback (most recent call last):
  File "file.py", line 14, in <module>
    p2 = math.sqrt(b*b -4*a*c)
ValueError: math domain error

Answer 1

你必须这样做才能使math.sqrt不接受负值。因此，如果b * b-4 * a * c是负数，那么您将得到数学域错误。解决这个问题的一种方法是事先检查sqrt操作中的值是否为带if语句的负值。

Answer 2

我假设你不想寻找想象的根源如果你是，你应该看看cmath

您应该将该块更改为

try:
    p1 = b * -1
    math.sqrt(b**2 - 4*a*c)
    p3 = 2*a
    s1 = (p1+p2)/p3
    s2 = (p1-p2)/p3
    print("Soluciones :", s1, " y ", s2)
except ValueError:
    print("No real solution")

这称为异常处理，对于这种情况，它是完美的工具。它将转到except语句的唯一时间是math.sqrt（）被赋予否定。在这种情况下，根是虚构的，所以打印（“没有真正的解决方案”）或任何你想要的错误信息！

ValueError：二级方程中的数学域错误

2 个答案: