r - 没有数据时停止消息的语法是什么
问题描述
我正在将一些数据导入 R,如果没有文件或文件中没有数据,我希望代码停止运行。我正在使用 base R 和 readxl。请问你能帮忙语法吗?
我试过了
if (dim(Llatest) == NULL) {stop('STOP NO DATA')}
if (dim(Llatest)[1] == 0) + stop('STOP NO DATA')}
if (isTRUE(dim(Llatest) == NULL)) {stop('STOP NO DATA')}
从 Sep19import.xlsx 导入的一些数据
ID Code Received Actioned Decision
1 123 Jul 01 2019 Sep 02 2019 Hold
2 456 Jul 11 2019 Sep 13 2019 No action
3 789 Nov 26 2018 Sep 25 2019 Investigate
4 321 Sep 12 2019 Sep 12 2019 Await decision
5 654 Aug 30 2019 Sep 26 2019 Hold
6 987 Feb 22 2019 Sep 02 2019 Investigate
获取要导入的文件列表
LFiles <- list.files(path = "C:/Projects/Sep/code", pattern = "*import.xlsx", full.names = TRUE)
***如果 LFiles 为空,我希望在此停止
识别最新文件
Llatest <- subset(LFiles, LFiles == max(LFiles))
从文件中提取数据
LMonthly <- read_excel(Llatest)
***如果 LMonthly 是空的,我想停在这里
收到错误消息 - 没有非缺失参数,返回 NA 我希望输出为“停止无数据”
解决方案
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