解决方案1＆amp; 2

Question

我开发了以下用于通过并行计算导入一系列压缩CSV的代码。

我的问题是：

某些ZIP文件（其中包含CSV）已损坏，无法打开。
执行parRapply后，我只能看到last.warning变量错误，因为我知道哪个CSV在每个节点都出现故障，但我看不到所有警告，一次只能看到1个。

所以：

为了显示所有节点中所有警告的列表，我在考虑在代码中使用以下函数：
```
warnings(DISPOIN_CSV_List <- parRapply(c1, DISPOIN_DIR_REL, parRaplly_Function))
```
这会有用吗？
此外，如何在应用该功能之前检查是否可以打开CSV，并为这些CSV创建一个空的data.frame。

## -----------------------------------------------------------------------------
## Packages
## -----------------------------------------------------------------------------

# update.packages("RODBC")
# update.packages("tidyverse")

## -----------------------------------------------------------------------------
## Libraries
## -----------------------------------------------------------------------------

suppressMessages(require(RODBC))
suppressMessages(require(tidyverse))
suppressMessages(require(parallel))

## -----------------------------------------------------------------------------
## CMD: Command for DISPOIN's Directory Acquisition
## -----------------------------------------------------------------------------

# shell(cmd = 'pushd "\\srvdiscsv\data" && dir *AL*.zip /b /s > D:\DISPOIN_Data_Directories.csv && popd')

## -----------------------------------------------------------------------------
## RODBC
## -----------------------------------------------------------------------------

## A) MariaDB Connection String

con <- odbcConnect("MariaDB_Tornado24")

invisible(sqlQuery(con, "USE dispoin;"))

# B) Import R Data Directories from MariaDB

DISPOIN_DIR_REL <- as_tibble(sqlFetch(con, "dispoin.t_DISPOIN_DIR_REL"))

odbcClose(con)

# C) Import Zipped CSV data into List of Dataframes, which latter on are compiled as a single dataframe by
#    means of rbind

  # C.1) parRapply Function Initialization:

  parRaplly_Function <- function (DISPOIN_CSV_Row)
  {
    return(read_csv2(
      file = DISPOIN_CSV_Row,
      col_names = c(
        "SCADA",
        "TAG",
        "ID_del_AEG",
        "Descripcion",
        "Time_ON",
        "Time_OFF",
        "Delta_Time",
        "Comentario",
        "Es_Alarma",
        "Es_Ultima",
        "Comentarios"),
      col_types = cols(
        "SCADA" = "c",
        "TAG" = "c",
        "ID_del_AEG" = "c",
        "Descripcion" = "c",
        "Time_ON" = "c",
        "Time_OFF" = "c",
        "Delta_Time" = "c",
        "Comentario" = "c",
        "Es_Alarma" = "c",
        "Es_Ultima" = "c",
        "Comentarios" = "c"),
      locale = default_locale(),
      na = c("", " "),
      quoted_na = TRUE,
      quote = "\"",
      comment = "",
      trim_ws = TRUE,
      skip = 0,
      n_max = Inf,
      guess_max = min(1000, n_max),
      progress = FALSE))
  }

  # C.2) parallel Package: Environment Settings

  no_cores <- detectCores()

  c1 <- makeCluster(no_cores)

  invisible(clusterEvalQ(c1, library(readr)))

  setDefaultCluster(c1)

  # C.3) parRapply Function Application:

  DISPOIN_CSV_List <- parRapply(c1, DISPOIN_DIR_REL, parRaplly_Function)

  suppressWarnings(stopCluster(c1))

# D) List's Tibbles Compilation into a single Tibble:

  DISPOIN_CSV <- do.call(rbind, DISPOIN_CSV_List)

# E) Write Compiled Table into CSV:

  write_csv(
    DISPOIN_CSV, 
    path = file.path("D:/MySQL/R", "DISPOIN_CSV.csv"), 
    na = "\\N", 
    append = FALSE, 
    col_names = TRUE)

# F) Data Cleaning: Environment Variable Removal

  rm(list=ls())

解决方案1＆amp; 2

我在r-help邮件列表中问了同样的问题，这就是他们给我的答案：

使用tryCatch（）。

，而不是

result <- read_csv2(file)

使用

result <- tryCatch(read_csv2(file), error=function(e) makeEmptyDataFrame(conditionMessage(e)))

其中：

makeEmptyDataFrame（msg = NULL）是一个函数（您编写的），它返回一个没有行但具有正确列名和类型的data.frame。我用一个msg（消息）参数显示它，因为您可能希望将错误消息作为属性附加到它，以便您可以看到出错的地方。

R：打印所有并行节点中出现的所有警告

解决方案1＆amp; 2

0 个答案: