使用一个正则表达式匹配一个空格后跟一个数字或一个大写字母，然后用一个分隔符替换所述匹配，最后将结果字符串解析为CSV文档：

# read target file into memory for later extraction
$fileContents = Get-Content C:\path\to\source\file.txt

# define error report, replace with `Get-Content` if data if coming from file too
$errorReport = @'
Error code Line number
1234 00232,00233,00787
3333 00444
1111 01232,2132
'@

# replace the middle space and parse as CSV
$errorMappingList = $errorReport -replace '(?-i) (?=\p{Lu}|\d)', '|' |ConvertFrom-Csv -Delimiter '|'

# go through each entry in the error mapping list
foreach($errorMapping in $errorMappingList){
    # go through each line number associated with the error code
    foreach($lineNo in $errorMapping.'Line Number' -split ','){
        # extract the line from the file contents, output 1 new object per line extracted
        [pscustomobject]@{
            ErrorCode  = $errorMapping.'Error code'
            LineNumber = $lineNo
            Line       = $fileContents[$lineNo - 1]
        }
    }
}