警告消息：条件的长度> 1，只使用第一个元素

Question

我正在尝试评估用于进行某些预测的不同算法的分数。我使用scoring_model作为函数

scoring_model <- function(observed, predicted) {

 if (observed < predicted) 
    score <- ((exp(-(observed - predicted)/10)) -1 )

   else if(observed > predicted) 
    score <- ((exp((observed - predicted)/13)) -1 )

  else score <- 0

  metrics_score <- c("Score" = score)

  return(metrics_score)
}

运行此代码后，我收到错误

##Warning message:

##In if (observed < predicted) score <- ((exp(-(observed - predicted)/10)) -  :
##the condition has length > 1 and only the first element will be used