I am looping through multiple XML files in a directory. Each file has identical structure:

```
<input>
    <filePattern>
        <marketCode>cbf_d</marketCode>
        <format>txt</format>
    </filePattern>
</input>
<input>
    <filePattern>
        <marketCode>lvd_cbf_b</marketCode>
        <format>csv</format>
    </filePattern>
</input>
<input>
    <filePattern>
        <marketCode>cbf_a</marketCode>
        <format>zip</format>
    </filePattern>
</input>

```

My purpose is to loop through each `input` node within a file, extract `InnerText` values from `marketCode` and `format` and then concatenate them into a single string:

```
Get-ChildItem -Path 'C:\test\cbf\*merge*' -Recurse |
ForEach-Object {
    $xml_file = $_ 

    $content = [xml](Get-Content $xml_file)
    $nodes = $content.SelectNodes('//input')    

    foreach ($node in $nodes) {
        $marketCode = $node.SelectNodes('//input/filePattern/marketCode').InnerText
        $format = $node.SelectNodes('//input/filePattern/format').InnerText

    }
    #Trying to cancatenate InnerText values here:
    $marketCode + '_' + $format

}

```

The output that I get:

```
cbf_d
lvd_cbf_b
cbf_a
_
txt
csv
zip

```

The output that I expect:

```
cbf_d_txt
lvd_cbf_b_csv
cbf_a_zip

```

How to properly concatenate values of `InnerText`?