计算2年的差异

Question

一年是出生年，另一年是季节年；目标是计算特定季节的年龄（以年为单位）。我想获取此信息并在合并数据集中创建一个新字段 (master$playerAge)。我收到一个不熟悉的错误，不确定是什么原因造成的。我已经确认merged.all$yearID 和merged.all$birthYear 都存在于merged.all 中。任何帮助表示赞赏。

代码sn-p：

## calculate age from birthYear and YearId
master$playerAge <- paste(merged.all$yearId - merged.all$birthYear)

Error:
Error in `[<-.data.table`(x, j = name, value = value) : 
  RHS of assignment to new column 'playerAge' is zero length 
  but not empty list(). For new columns the RHS must either be 
  empty list() to create an empty list column, or, have length > 0; 
  e.g. NA_integer_, 0L, etc.

输入（）：

Names = c("playerID", "yearID", "teamID", "lgID", "stint", "G", "AB", "R", "SO", "IBB", "HBP" 、“SH”、“SF”、“GIDP”、“salary”、“birthYear”、“birthMonth”、“birthDay”、“birthCountry”、“birthState”、“birthCity”、“deathYear”、“deathMonth”、“ deathDay”、“deathCountry”、“deathState”、“deathCity”、“nameFirst”、“nameLast”、“nameGiven”、“weight”、“height”、“bats”、“throws”、“debut”、“finalGame” , "retroID", "bbrefID", "name", "dob"), sorted = "playerID", class= c("data.table", "data.frame"), row.names = c(NA, - 6L), .internal.selfref = ) > –

Answer 1

我在您的代码中看到了拼写错误（“ID”中的大小“D”字母）：

我都确认了

merged.all$yearID and merged.all$birthYear 

master$playerAge <- paste(merged.all$yearId - merged.all$birthYear)