'Why has this PowerShell Object changed? What is the difference?

foreach ($line in $test) {
    $line.GetType()
    $newline = $line -split ("<.*?>") -split ("{.*?}") # remove html and css tags
    $newline.GetType()
}

I came across this when trying to use the .Trim() method on $newline. It works, but the intellisense did not indicate that it would. I thought .Trim() would only work on String Objects (BaseType:System.Object), but in this instance, it seems to work on String[] Objects as well (BaseType:System.Array).

$line.GetType() returns

IsPublic IsSerial Name                                     BaseType                                                                                
-------- -------- ----                                     --------                                                                                
True     True     String                                   System.Object

$newline.GetType() returns

IsPublic IsSerial Name                                     BaseType                                                                                
-------- -------- ----                                     --------                                                                                
True     True     String[]                                 System.Array

First off, I would like to know why my original string was converted to an array, assuming it's the return value of -split... Is it now an array of characters? I am a little confused.

Secondly, if there is a good answer, why do the string methods work on what is technically an array?

Coming from Python and C/C++, thanks.

arraysstringpowershell


Solution 1:[1]

Santiago Squarzon's helpful answer provides an effective solution to what your code is trying to do.

To answer your questions as asked, building on Lasse V. Karlsen's helpful comments:

I would like to know why my original string was converted to an array, assuming it's the return value of -split... Is it now an array of characters?

The -split operator splits a string or array of strings into substrings by a given separator regex and returns the substrings as a string array ([string[]])

 'foo|bar' -split '\|' # -> [string[]] ('foo', 'bar')

  • With an array as input, the splitting operation is performed on each element separately, and the per-element result arrays are concatenated to form a single, flat array.

    'foo|bar', 'baz|quux' -split '\|' # -> [string[]] ('foo', 'bar', 'baz', 'quux')

Secondly, if there is a good answer, why do the string methods work on what is technically an array?

What you're seeing is a feature previously semi-officially known as member enumeration and soon to be officially termed member-access enumeration: The ability to access a member (a property or a method) on a collection and have it implicitly applied to each of its elements, with the results getting collected in an array (for two or more elements).

Quick example:

# .Trim() is called on *each element* of the input array.
PS> (' foo', 'bar ').Trim() | ForEach-Object { "[$_]" }
[foo]
[bar]

Solution 2:[2]

Lasse V. Karlsen already provided the key information to understand why the strings ($line) are converted to string[] after being split. What you have most likely wanted to use in this case was the -replace operator which is regex compatible.

Using below as an example:

$htmlcss = @'
table {
  font-family: arial, sans-serif;
  border-collapse: collapse;
  width: 100%;
}

td, th {
  border: 1px solid #dddddd;
  text-align: left;
  padding: 8px;
}

tr:nth-child(even) {
  background-color: #dddddd;
}

</style>
</head>
<body>
<h2>HTML Table</h2>
<table>
  <tr>
    <th>Company</th>
    <th>Contact</th>
    <th>Country</th>
  </tr>
  <tr>
    <td>Alfreds Futterkiste</td>
    <td>Maria Anders</td>
    <td>Germany</td>
  </tr>
</table>
</body>
</html>
'@

Using -replace to remove the HTML and CSS tags then -split to get a string[] and lastly filter the array to skip the empty lines:

$htmlcss -replace '(?s)<.*?>|\{.*?\}' -split '\r?\n' |
Where-Object { $_ -match '\S' }

Results in:

table 
td, th 
tr:nth-child(even) 
HTML Table
    Company
    Contact
    Country
    Alfreds Futterkiste
    Maria Anders
    Germany

Note, regarding \{.*?\}, for this regex to work you must use it with a string or multi-line string. It will not work with a string array string[]. You will also need to enable the (?s) flag. Supposing you were reading this from a file you would want to use the -Raw switch on Get-Content.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1
Solution 2

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