R中的四部分公式語法

我在R中使用lfe包進行高維固定效果。試圖在沒有協變量的情況下運行時遇到麻煩。也就是說，只有固定的效果。我的代碼是：R中的四部分公式語法

library(lfe) 
data=read.csv("path_to//my_data.csv") 

y <- cbind(col1) 
x <- cbind(col2) 

est <- felm(y ~ 0|x, data)

然而，最後一行給出了錯誤：

Error in model.frame.default(terms(formula, lhs = lhs, rhs = rhs, data = data, : 
    variable lengths differ (found for 'x')

請注意，我用正確的語法調用它，根據四部分組成的配方格式，可以看出在documentation第20頁，在那裏說：

The formula specification is a response variable followed by a four part formula. The first part consists of ordinary covariates, the second part consists of factors to be projected out. The third part is an IV-specification. The fourth part is a cluster specification for the standard errors. I.e. something like y ~ x1 + x2 | f1 + f2 | (Q|W ~ x3+x4) | clu1 + clu2 where y is the response, x1,x2 are ordinary covariates, f1,f2 are factors to be projected out, Q and W are covariates which are instrumented by x3 and x4 , and clu1,clu2 are factors to be used for computing cluster robust standard errors. Parts that are not used should be specified as 0 , except if it’s at the end of the formula, where they can be omitted.

來源

2017-04-02 splinter

一個無關點，使用'attach'是一個壞主意。我幾乎肯定'felm'有一個'data'參數。改用它。你應該可以把它寫成'est < - felm（col1〜0 | col2，data = data）'。 – lmo

事實證明，這是一個語法問題，通過@lmo的建議。如果我做的：

est <- felm(col1 ~ 0|col1data)

那麼有沒有錯誤，它的工作原理

來源

2017-04-02 18:54:18 splinter

R中的四部分公式語法

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