R语言中如何记录程序运行的时间

 

1、

start <- Sys.time()     ## 记录
Sys.sleep(20)           ## 停止20s
end <- Sys.time()       ## 记录
elapse <- end - start   ## 计算
print(elapse)           ## 打印

 

 

2、

start <- Sys.time()
Sys.sleep(70)
end <- Sys.time()
elapse <- end - start
print(elapse)              ## 自动转换时间输出格式

 

3、写入文件

start <- Sys.time()
Sys.sleep(70)    ## commands
end <- Sys.time()
process <- paste(start, end, sep = "---")
write.table(process, "time.txt")
elapsed <- as.numeric(difftime(end, start, units = 'sec'))
write.table(elapsed, "time.txt", row.names = "secs:", col.names = F,append = T)