黄大明数据分析

摘要： 官方帮助文档如下写的：Usagerep(x, ...)rep.int(x, times)rep_len(x, length.out)Argumentsxa vector (of any mode including a list) or a factor or (forreponly) aPOSIXctorPOSIXltorDateobject; or an S4 object containing such an object....further arguments to be passed to or from other methods. For the internal defaul 阅读全文

摘要： unlist函数的使用 阅读全文