在R和summary（）函數中創建因子水平

Question

因此，我正在學習R。我在這里關注此教程： https : //www.datacamp.com/courses/introduction-to-r/chapter-4-factors?ex=4

那就是我輸入的內容：

survey_vector <- c("M","F","F","M","M")
factor_survey_vector <- factor(survey_vector)

# Your code here
levels(factor_survey_vector) <- c("Female","Male")

factor_survey_vector
summary(factor_survey_vector)

這就是R中提示的內容

> factor_survey_vector
[1] Male   Female Female Male   Male  
Levels: Female Male
> summary(factor_survey_vector)
Female   Male 
     2      3 

雖然我了解factor_survey_vector的提示， factor_survey_vector我不了解summary(factor_survey_vector)的提示。 R怎么知道有2個雌性和3個雄性？ 我只將向量c("Female","Male")分配給levels(factor_survey_vector) 。 如何解釋每個M是男性，每個F是女性？ 我想我正在監督一些非常瑣碎的事情？！

Answer 1

您可以使用str()查看底層結構：

> survey_vector <- c("M","F","F","M","M")
> factor_survey_vector <- factor(survey_vector)
> 
> 
> str(factor_survey_vector)
 Factor w/ 2 levels "F","M": 2 1 1 2 2

因此factor_survey_vector是2 1 1 2 2 2，級別1為“ F”，級別2為“ M”

> levels(factor_survey_vector) <- c("Female","Male")
> str(factor_survey_vector)
 Factor w/ 2 levels "Female","Male": 2 1 1 2 2

唯一的區別是級別標簽已更改。 現在1是女性，2是男性。