如何使用 Powershell 在 table 中更改多个 headers

Question

我正在尝试更改我的代码中的多个 header 名称，这些名称正在从 this site 中提取 Team Statistics table 我不确定在我的代码中在哪里手动更改它们。

例如，我尝试在添加“TEAM”header 的行中手动将 header 8, GF 更改为 GFPG，但是我得到错误：

Exception calling "Add" with "2" argument(s): "Item has already been added. Key in dictionary: 'GF' Key being added: 'GF'" At C:\NHLScraper.ps1:32 char:5 + $objHash.Add($headers[$j],$rowdata[$j])

我的代码：

$url = "https://www.hockey-reference.com/leagues/NHL_2020.html"

#getting the data
$data = Invoke-WebRequest $url

#grab the third table
$table = $data.ParsedHtml.getElementsByTagName("table") | Select -skip 2 | Select -First 1


#get the rows of the Team Statistics table
$rows = $table.rows

#get table headers
$headers = $rows.item(1).children | select -ExpandProperty InnerText

#count the number of rows
$NumOfRows = $rows | Measure-Object

#Manually injecting TEAM header
$headers = @($headers[0];'TEAM';$headers[1..($headers.Length-1)])

#enumerate the remaining rows (we need to skip the header row) and create a custom object
$out = for ($i=2;$i -lt $NumofRows.Count;$i++) {
 #define an empty hashtable
 $objHash=[ordered]@{}
 #getting the child rows
 $rowdata = $rows.item($i).children | select -ExpandProperty InnerText 
 for ($j=0;$j -lt $headers.count;$j++) {
    #add each row of data to the hash table using the correlated table header value
    $objHash.Add($headers[$j],$rowdata[$j])
  }

  #turn the hashtable into a custom object
  [pscustomobject]$objHash
}

$out | Select TEAM,AvAge,GP,W,L,OL,PTS,PTS%,GF,GA,SOW,SOL,SRS,SOS,TG/G,EVGF,EVGA,PP,PPO,PP%,PPA,PPOA,PK%,SH,SHA,PIM/G,oPIM/G,S,S%,SA,SV%,SO -SkipLast 1 | Export-Csv -Path "C:$((Get-Date).ToString("'NHL Stats' yyyy-MM-dd")).csv" -NoTypeInformation

Answer 1

您可以添加一个条件来检查密钥是否已经添加，如果是，更新它或忽略它，

if (!$objHash.Contains(headers[$j]))
    $objHash.Add($headers[$j],$rowdata[$j])

else
    $objHash[$headers[$j]] = $rowdata[$j] # Overwrite values

但是看了你的代码几次后，这没有意义，

$out = for ($i=2;$i -lt $NumofRows.Count;$i++) {
 #define an empty hashtable
 $objHash=[ordered]@{}         # Overwritten each loop???
 #getting the child rows
 $rowdata = $rows.item($i).children | select -ExpandProperty InnerText 
 for ($j=0;$j -lt $headers.count;$j++) {
    #add each row of data to the hash table using the correlated table header value
    $objHash.Add($headers[$j],$rowdata[$j])   # Dictionary cannot have duplicate keys
  }

  #turn the hashtable into a custom object
  [pscustomobject]$objHash    # what do you do with this?
}

您循环了 x 次并且每次都覆盖了 $objHash。唯一会返回的是在最后一个循环中创建的内容。

建议的解决方案

您可以使用另一个变量来跟踪您正在创建的所有哈希表，同时确保没有插入会引发异常的重复键。

# If you want to change the header value from GF to GFPG, you can do that in the place you have defined $headers


#get table headers
$headers = $rows.item(1).children | select -ExpandProperty InnerText
$headers = $headers | % { if ($_ -eq "GF") { "GFPG" }  else { $_ }} 

#count the number of rows
$NumOfRows = $rows | Measure-Object

#Manually injecting TEAM header
$headers = @($headers[0];'TEAM';$headers[1..($headers.Length-1)])

#enumerate the remaining rows (we need to skip the header row) and create a custom object
$allData = @{}
$out = for ($i=2;$i -lt $NumofRows.Count;$i++) {
 #define an empty hashtable
 $objHash=[ordered]@{}
 #getting the child rows
 $rowdata = $rows.item($i).children | select -ExpandProperty InnerText 
 for ($j=0;$j -lt $headers.count;$j++) {
    #add each row of data to the hash table using the correlated table header value
    $objHash[$headers[$j]] = $rowdata[$j]        
  }

  #turn the hashtable into a custom object
  [pscustomobject]$objHash
  $allData.Add($i, $objHash)
}

我使用 $AllData 和 i 作为键来存储以后可以访问的每个结果。

如何使用 Powershell 在 table 中更改多个 headers

How to change multiple headers in a table using Powershell

windows

powershell

html-parsing

web-scraping

powershell-4.0