你能给我解释一下打电话和打电话的区别吗

python -m mymod1 mymod2.py args

and

python mymod1.py mymod2.py args

在这两种情况下，似乎都调用了mymod1.py和sys. py。argv是

['mymod1.py', 'mymod2.py', 'args']

那么-m开关是干什么用的呢?

我使用实体框架5.0代码第一;

public class Entity
 {
   [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
   public string EntityId { get; set;}
   public int FirstColumn  { get; set;}
   public int SecondColumn  { get; set;}
 }

我想让FirstColumn和SecondColumn的组合是唯一的。

例子:

Id  FirstColumn  SecondColumn 
1       1              1       = OK
2       2              1       = OK
3       3              3       = OK
5       3              1       = THIS OK 
4       3              3       = GRRRRR! HERE ERROR

有办法吗?

我正在尝试为一个使用蓝牙通信的应用程序启动一个颤振项目。我用的是颤振蓝。

不幸的是，当试图运行(在Android设备上)我创建的第一个示例时，我遇到了以下错误:

FAILURE: Build failed with an exception.

  * What went wrong:
  Execution failed for task ':app:processDebugManifest'.
  > Manifest merger failed : uses-sdk:minSdkVersion 16 cannot be smaller than version 19 declared in library [:flutter_blue] /home/maldus/Projects/flutter/polmac/build/flutter_blue/intermediates/manifests/full/debug/AndroidManifest.xml as the library might be using APIs not available in 16
    Suggestion: use a compatible library with a minSdk of at most 16,
            or increase this project's minSdk version to at least 19,
            or use tools:overrideLibrary="com.pauldemarco.flutterblue" to force usage (may lead to runtime failures)

如果我在Android Studio，我知道如何提升Android minSdkVersion，但在一个flutter项目(使用VSCode)，我有点迷失。

是否有可能增加minSdkVersion与颤振，以及如何?

我来自熊猫的背景，我习惯了从CSV文件读取数据到一个dataframe，然后简单地改变列名使用简单的命令有用的东西:

df.columns = new_column_name_list

然而，这在使用sqlContext创建的PySpark数据框架中是行不通的。 我能想到的唯一解决办法是:

df = sqlContext.read.format("com.databricks.spark.csv").options(header='false', inferschema='true', delimiter='\t').load("data.txt")
oldSchema = df.schema
for i,k in enumerate(oldSchema.fields):
  k.name = new_column_name_list[i]
df = sqlContext.read.format("com.databricks.spark.csv").options(header='false', delimiter='\t').load("data.txt", schema=oldSchema)

这基本上是定义变量两次，首先推断模式，然后重命名列名，然后用更新的模式再次加载数据框架。

有没有更好更有效的方法来做到这一点，就像我们对熊猫做的那样?

我的Spark版本是1.5.0

我运行Ubuntu 9:10，安装了一个名为M2Crypto的包(版本为0.19.1)。我需要下载、构建和安装最新版本的M2Crypto包(0.20.2)。

0.19.1包的文件位于多个位置，包括(/usr/share/ pshared和/usr/lib/pymodules.python2.6)。

在安装0.20.2之前，如何从系统中完全卸载0.19.1版本?

我有这样一个场景:

public class Member
{
    public int MemberID { get; set; }

    public string FirstName { get; set; }
    public string LastName { get; set; }

    public virtual ICollection<Comment> Comments { get; set; }
}

public class Comment
{
    public int CommentID { get; set; }
    public string Message { get; set; }

    public virtual ICollection<Member> Members { get; set; }
}

public class MemberComment
{
    public int MemberID { get; set; }
    public int CommentID { get; set; }
    public int Something { get; set; }
    public string SomethingElse { get; set; }
}

如何配置我与fluent API的关联?或者是否有更好的方法来创建关联表?

我只是想知道在Apache Spark中RDD和DataFrame (Spark 2.0.0 DataFrame只是数据集[行]的类型别名)之间的区别是什么?

你能把一个转换成另一个吗?

有人能发布一个通过终端设置ANDROID_HOME的工作解决方案吗?

我到Android-SDK的路径是/Applications/ADT/sdk。

我知道这是一个非常基本的问题，但令我惊讶的是，我找不到任何关于Android SDK构建工具的文档。 除了Android SDK Tools和Android SDK Platform-tools，还有一堆Android SDK Build-tools，如图所示。有没有人能指出一个来源来解释所有这些，并帮助澄清一个特定版本的Android SDK构建工具是如何被选择使用的?

编辑(2014-02-27):

我仍然没有完全理解所有的工具。以下是我根据谷歌最新的资料所作的有限了解:

Android SDK Build-tools used to be components of Android SDK Platform-tools. They have been decoupled from Android SDK Platform-tools, so that the build tools can be updated independently of the integrated development environment (IDE) components. Android SDK Platform-tools are customized to support the features of the latest Android platform. They are backward compatible so that you always use the latest update of Android SDK Platform-tools even your app targets older Android platforms. SDK tools are platform independent and are required no matter which Android platform you are developing on.

I still do not understand the rationale of taking Android SDK Build-tools out of Android SDK Platform-tools which has a single instance and is easy to manage the update. The only possible reason that I can think of is that some apps have to rely on older build components to build them. Google's document mentions this, but does not explain why. Looking at the release notes, you will notice that updates of Android SDK Build-tools are primarily for fixing bugs or/add support for new platforms. The only reason that I can think of for some apps to use older versions of Android SDK Build-tools is that they rely on certain bugs of Android SDK Build-tools. These apps would not function normally without being built with these bugs. I wish Google could explain this better by giving one or two examples showing why these bugs in the tools are critical for certain apps.

我试着通读关于兄弟姐妹导入的问题，甚至 软件包文档，但我还没找到答案。

结构如下:

├── LICENSE.md
├── README.md
├── api
│   ├── __init__.py
│   ├── api.py
│   └── api_key.py
├── examples
│   ├── __init__.py
│   ├── example_one.py
│   └── example_two.py
└── tests
│   ├── __init__.py
│   └── test_one.py

示例和测试目录中的脚本如何从 API模块和从命令行运行?

另外，我希望避免对每个文件都使用难看的sys.path.insert。肯定 这可以在Python中完成，对吧?