Confronting .NET myths

本文作者在关于.NET的演讲中,遇到很多对.NET和Web服务的误解。作者澄清了三大误区:一是.NET不仅用于Web服务;二是使用Web服务不意味着符合.NET标准;三是在.NET框架上构建应用无需使用.NET My Services。同时指出统一品牌虽有好处,但也有风险。

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.NET & Beyond: Confronting .NET myths

 

By David Chappell

 

At my talks about .NET this year, I've been running into many of the same misconceptions. Since many of them revolve around Web services, I'd like to clear up some of the confusion out there. Here are my candidates for the top three myths about .NET and Web services:

 

1. .NET is only about Web services. People often tell me that since they don't want to build Web services right now, they don't need to use the .NET Framework. In fact, the .NET Framework supports all kinds of applications. It does contain first-rate support for building Web services, but it's also useful for creating many other kinds of software, including local Windows applications, conventional multitier browser applications and more.

 

This myth exists because Microsoft's .NET marketing message has been so focused on Web services. Perhaps this is an artifact of the company's obsession with promoting the newest thing, or maybe the marketing team decided its target audience would understand only one message. Since the .NET initiative is a diverse set of software, this singularity of focus distorts reality. .NET is about Web services, certainly, but it's also about many other things.

 

2. Anybody who's using Web services is .NET-compliant. I have no idea what it means to be ".NET-compliant," and I doubt anyone else does either. Yet I hear this phrase quite often. Although the core Web services technologies came largely from Microsoft, virtually every major vendor now supports them. In fact, Web services look like the best chance we have of linking software from different vendors into a coherent whole. That people associate Web services with .NET is probably a good thing for Microsoft, so perhaps that's a positive result of the company's very focused marketing message. But Web services needn't imply .NET.

 

It's no small irony that the technologies most likely to knit together our diverse world come largely from Microsoft. Who would have imagined this legendarily proprietary vendor would be the source of such critical multivendor standards? Nevertheless, Web services are no longer purely a Microsoft technology, and that's a good thing. By giving them to the World Wide Web Consortium (W3C), Microsoft and the other companies behind Web services have made these technologies much more useful than they otherwise would have been.

 

3. Building applications on the .NET Framework requires using .NET My Services. .NET My Services is mostly a set of Web services that can store information about people, then allow applications to access that information. But .NET My Services also includes Passport, an Internet-based service for authenticating users. Some people, especially those who don't live in the U.S., are nervous about Passport. And since both it and the .NET Framework are part of .NET, these people tend to jump to the conclusion that using the .NET Framework also requires the use of Passport.

 

This is, of course, completely wrong. The .NET Framework and .NET My Services, including Passport, have almost nothing to do with each other. While the Framework is a good foundation for building applications that use .NET My Services, these services are explicitly designed to be accessible from non-Microsoft systems. In fact, one of the most visible demos for .NET My Services at Microsoft's 2001 Professional Developers Conference was written in Java and relied on Apache.

 

Microsoft is taking a big risk by grouping all of these diverse technologies under the .NET brand. Like any new and innovative technology, .NET My Services is not guaranteed to succeed. What happens if it fails, or simply takes a long time to find its customer base? This should have no impact on the success of the .NET Framework or other parts of .NET, yet a substantial segment of the market is unlikely to distinguish between these largely independent efforts. If any part of the .NET initiative fails to thrive, it's likely to damage other unrelated parts. Having a unified brand is good in many ways, but it's not without its pitfalls.

 

These are my top candidates for myths about .NET and Web services, but they're certainly not the only choices. As Walt Whitman wrote in "Song of Myself" in Leaves of Grass, "I am large, I contain multitudes." .NET can be described in the same way.

 

If you have a favorite .NET myth, send it to me. Together, we can fight for clarity in this mass of new technology.


David Chappell is principal at Chappell & Associates, an education and consulting firm focused on enterprise software technologies. He can be reached via E-mail at david@davidchappell.com.

df head(df) sleep_hours1 <- df$When.have.you.usually.gone.to.bed.in.the.past.month. sleep_hours2<-df$What.time.have.you.usually.gotten.up.in.the.morning.in.the.past.month. fall_asleep_time <- df$How.long.has.it.taken.you.to.fall.asleep.each.night.in.the.past.month. var1<-df$Cannot.get.to.sleep.within.30.minutes var2<-df$Wake.up.in.the.middle.of.the.night.or.early.morning var3<-df$Have.to.get.up.to.use.the.bathroom var4<-df$Cough.or.snore.loudly var5<-df$Feel.too.cold var6<-df$Feel.too.hot var7<-df$Have.bad.dreams var8<-df$Have.pain disturbance_vars <- cbind(var1, var2, var3, var4, var5, var6, var7, var8) colnames(disturbance_vars) <- c("Cannot get to sleep within 30 minutes", "Wake up in the middle of the night or early morning", "Have to get up to use the bathroom", "Cough or snore loudly", "Feel too cold", "Feel too hot", "Have bad dreams", "Have pain") disturbance_vars gender <- as.factor(df[["Gender"]]) gender X <- data.frame( fall_asleep_time, sleep_hours1, sleep_hours2, disturbance_vars, gender ) s1<-df$You.have.to.submit.an.assignment.in.less.than.a.day s2<-df$A.week.before.exams s3<-df$Asking.for.an.extra.ketchup.packet.at.a.restaurant s4<-df$Meeting.a.new.person s5<-df$Asking.for.help s6<-df$Confronting.someone s7<-df$Doing.something.without.help stress_cols <- cbind(s1,s2,s3,s4,s5,s6,s7) colnames(stress_cols) <- c("You have to submit an assignment in less than a day", "A week before exams", "Asking for an extra ketchup packet at a restaurant", "Meeting a new person", "Asking for help", "Confronting someone", "Doing something without help") stress_scores <- rowMeans(stress_cols) Y <- ifelse(stress_scores > median(stress_scores), 1, 0) Y model <- glm( Y ~., data = X, family = binomial(link = "logit") ) summary(model) step_model <- step( model, direction = "both", trace = 1 ) summary(step_model) 这是我的数据,然后我每次都会出现[.data.frame`(model_data, , rn, drop = FALSE):这个错误
06-05
<think>我们正在解决使用ggeffects包时出现的错误:`错误于`[.data.frame`(model_data,,rn,drop=FALSE):选择了未定义的列`结合之前分析,该错误通常是因为ggeffects在尝试获取模型数据时,找不到模型中使用的一个或多个变量(即列名不匹配)。以下为详细解决方案,特别关注glm模型与ggeffects的交互问题:###1.检查模型公式中的变量名与数据框列名完全一致在调用`glm`时,公式中的变量名必须与数据框`X`中的列名完全一致(包括大小写、空格和特殊字符)。在之前代码中,公式使用了以下变量:-sleep_hours1-Have.to.get.up.to.use.the.bathroom-Cough.or.snore.loudly-Feel.too.cold-gender使用`names(X)`检查数据框中这些列名是否完全一致。如果列名不一致,例如数据框中列名为"Havetogetuptousethebathroom"(带空格)而公式中为"Have.to.get.up.to.use.the.bathroom"(用点连接),则需要修改数据框列名或模型公式。推荐修改数据框列名为合法命名(无空格、无特殊字符,可使用下划线或点连接):```r#例如,将带空格的列名改为用下划线连接names(X)[names(X)=="Havetogetuptousethebathroom"]<-"Have_to_get_up_to_use_the_bathroom"#然后更新模型公式model<-glm(Y~sleep_hours1+Have_to_get_up_to_use_the_bathroom+Cough_or_snore_loudly+Feel_too_cold+gender,data=X,family=binomial(link="logit"))```或者,如果不想改变数据框列名,可以在公式中使用反引号包裹列名:```rmodel<-glm(Y~sleep_hours1+`Havetogetuptousethebathroom`+`Coughorsnoreloudly`+`Feeltoocold`+gender,data=X,family=binomial(link="logit"))```但是,使用反引号可能导致后续分析(如ggeffects)更容易出错,所以建议使用合法列名。###2.确保因子变量在数据框中已正确定义在之前的操作中,我们重新定义了`gender`因子的水平:```rX$gender<-factor(X$gender,levels=c("Female","Male"))```这步操作正确。但请确保其他因子变量(如果有)也已在数据框中定义好,而不是在模型公式中临时转换。错误示例:在公式内临时转换变量```rmodel<-glm(Y~factor(sleep_hours1)+...,#在公式内部临时转换data=X,family=binomial(link="logit"))```此时,ggeffects会尝试在数据框中寻找名为`factor(sleep_hours1)`的列,显然不存在。正确做法:预转换变量```r#在数据框中创建转换后的列X$sleep_hours1_factor<-factor(X$sleep_hours1)#然后使用新列model<-glm(Y~sleep_hours1_factor+...,data=X,family=binomial(link="logit"))```###3.显式指定newdata(使用原始数据框X)在调用`ggeffect`时,我们使用了参数`newdata=X`,但这里要注意:-`ggeffect`在后台会尝试从模型对象中提取数据,但当模型对象的数据环境不完整时(例如,建模时使用了数据框的子集或变换后的变量),需要显式提供数据框。-如果我们修改了数据框的列名(比如去掉了空格),而模型使用的是修改后的列名,那么我们应该使用修改后的数据框(即`X`)传递给`newdata`。但若在建模前已经修改了数据框列名,则此时应该没有问题。然而,错误可能出现在`ggeffect`试图从模型对象中提取数据时,模型对象存储的数据可能与当前环境中的数据框不一致。因此,建议在调用`ggeffect`时,显式指定`xlevels`参数,或确保在模型对象中存储了完整的数据(可使用`model.frame`查看):```r#查看模型使用的数据(模型框架)head(model.frame(model))```###4.检查ggeffects调用的terms参数在调用`ggeffect`时,`terms`参数应该只包含模型中的变量名(而且必须是数据框中存在的列名)。变量名不能用反引号包裹(除非变量名在数据框中就是以反引号形式存在,通常不需要)。```rgender_effect<-ggeffect(model,terms="gender",#这里必须与模型中的变量名完全相同newdata=X#提供数据框)```如果`terms`参数中写了一个在模型中不存在的变量名(比如拼写错误),也会报错。###5.重新拟合模型并检查如果上述步骤都做了,仍然报错,可以尝试以下步骤:a)重新拟合模型,确保模型使用的是处理过列名和因子后的数据框。b)在模型拟合后立即调用`ggeffect`,避免中间修改数据框。c)尝试使用`ggpredict`函数替代`ggeffect`(两者类似,但可能有不同的实现细节):```rgender_effect<-ggpredict(model,terms="gender",newdata=X)```###调试示例代码以下为修改后的完整示例代码:```r#假设原始数据框为X,且存在列名带空格等问题#第一步:修正列名(去掉空格等)names(X)<-gsub("","_",names(X))#将空格替换为下划线,也可以使用点替换#修正gender水平X$gender<-factor(X$gender,levels=c("Female","Male"))#拟合模型(使用新列名)model<-glm(Y~sleep_hours1+Have_to_get_up_to_use_the_bathroom+Cough_or_snore_loudly+Feel_too_cold+gender,data=X,family=binomial(link="logit"))#检查模型框架变量名print(names(model.frame(model)))#调用ggeffectslibrary(ggeffects)#使用ggpredict也可以尝试gender_effect<-ggeffect(model,terms="gender",newdata=X)#或者#gender_effect<-ggpredict(model,terms="gender",newdata=X)#如果没有报错,可以画图plot(gender_effect)```如果按照以上步骤处理,通常可以解决“未定义的列”错误。如果问题仍然存在,请提供`head(model.frame(model))`的输出,以便进一步诊断。§§相关问题§§1.R语言中如何批量修改数据框的列名?2.在glm模型中如何处理交互项?3.如何检查glm模型使用的数据框架?4.ggeffects包中ggeffect和ggpredict函数有何区别?</think> ### 解决R语言`glm`模型中"选择了未定义的列"错误 该错误通常发生在使用`ggeffects`包进行预测时,本质是**模型变量名与数据框列名不匹配**。以下是系统解决方案: #### 📌 核心解决方案 1. **验证列名一致性** 检查模型公式中的变量名必须**严格匹配**数据框列名(大小写敏感): ```r # 获取模型使用的变量名 all.vars(formula(model)) # 对比数据框实际列名 names(X) # 修复不一致列名(示例) colnames(X)[colnames(X) == "Have.to.get.up"] <- "Bathroom_need" # 消除特殊符号 ``` 2. **重构因子变量** 避免在公式中直接转换变量: ```r # 错误方式(导致ggeffects失效) model <- glm(Y ~ factor(gender), data = X) # 正确方式:预创建因子列 X$gender_f <- factor(X$gender, levels = c("Female", "Male")) model <- glm(Y ~ gender_f, data = X) ``` 3. **显式传递数据源** 确保`ggeffect`能定位原始数据: ```r # 添加model.frame重建数据环境 gender_effect <- ggeffect( model, terms = "gender_f", newdata = model.frame(model) # 强制使用模型数据框架 ) ``` #### 🛠️ 调试步骤 ```r # 1. 确认模型数据框架 head(model.frame(model)) # 2. 检查变量存储类型 sapply(model.frame(model), class) # 3. 测试基础预测功能 predict(model, newdata = X[1:3, ]) # 验证模型自身是否正常 ``` #### ✅ 完整修正示例 ```r # 步骤1: 清洁列名 X <- X %>% rename( Bathroom_need = "Have.to.get.up.to.use.the.bathroom", Snore = "Cough.or.snore.loudly" ) # 步骤2: 创建模型专用因子 X$gender_f <- factor(X$gender, levels = c("Female", "Male")) # 步骤3: 拟合模型 model <- glm( Y ~ sleep_hours1 + Bathroom_need + Snore + Feel.too.cold + gender_f, data = X, family = binomial ) # 步骤4: 安全调用ggeffects gender_effect <- ggeffect( model, terms = "gender_f", newdata = model.frame(model) # 关键参数 ) ``` #### ⚠️ 注意事项 1. 使用管道操作(`%>%`)时,通过`. %>% `显式传递数据环境 ```r X %>% model.frame() %>% ggeffect(terms = "gender_f") ``` 2. 对带空格的列名使用反引号: ```r ggeffect(model, terms = "`sleep hours`", newdata = X) ``` #### 📚 根本原因 此错误本质是**环境作用域问题**[^4]: - `glm()`存储公式时使用**符号化变量名** - `ggeffects`在调用`model.frame()`时依赖原始数据框环境 - 当列名被修改或存在特殊字符时出现映射断裂 ---
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