PowerShell 中存储在变量中的字符串的意外行为 [英] Unexpected behavior with a string stored in a variable in PowerShell
问题描述
我从 Excel 的 Cells.Find() 方法中得到了一些奇怪的行为:
I'm getting some odd behavior from Excel's Cells.Find() method:
我正在搜索的变量:
PS > $volumename
vol_01
PS > $volumename.GetType()
IsPublic IsSerial Name BaseType
-------- -------- ---- --------
True True String System.Object
不产生任何结果:
PS > $sheet.Cells.Find($volumename).Row
但是如果我手动复制并粘贴该变量的值:
but if I manually copy and paste the value of that variable:
PS > $volumename = "vol_01"
PS > $volumename.GetType()
IsPublic IsSerial Name BaseType
-------- -------- ---- --------
True True String System.Object
获取我期望的值:
PS > $sheet.Cells.Find($volumename).Row
198
在我看来，它们在各方面都完全相同.并非每种情况都会发生这种情况.一些卷名可以很好地通过，而另一些则不能.我确实删除了这篇文章的卷名，因为它有一个客户命名约定.与上述格式相同，并且与有效的卷名格式相同.
They appear to be exactly the same type in every way to me. This doesn't happen for every case. Some volume names passthrough fine while others do not. I did scrub the volume name for this post as it has a customers naming convention. It is the same format as above and the same format as the volume names that work.
推荐答案
以下代码段可用于检查字符串中的隐藏控制字符:
PS> & { [int[]] [char[]] $Args[0] | % { '0x{0:x} [{1}]' -f $_, [char] $_ } } "vol_01`n"
0x76 [v]
0x6f [o]
0x6c [l]
0x5f [_]
0x30 [0]
0x31 [1]
0xa [
]
第一列是每个字符的 Unicode 代码点(ASCII 码")，第二列是字符本身，用 [...]
The first column is each character's Unicode code point ("ASCII code"), and the second column the character itself, enclosed in [...]
请注意，我在字符串末尾添加了 "`n" - a 换行符 (U+000A) - 其代码点表示为十六进制.数字是 0xa.
Note that I've added "`n" at the end of the string - a newline character (U+000A) - whose code point expressed as a hex. number is 0xa.
如果在您的情况下，字符串中唯一不需要的部分是尾随空格，您可以按如下方式删除它们:
If, as in your case, the only unwanted part of the string is trailing whitespace, you can remove them as follows:
$volumename.TrimEnd() # trim trailing whitespace
在您的情况下，尾随空格是 0xa0，NO-BREAK SPACE (U+00A0)，.TrimEnd() 也将其删除，如 Tom Blodget 指出.
In your case, the trailing whitespace is 0xa0, the NO-BREAK SPACE (U+00A0), which .TrimEnd() also removes, as Tom Blodget points out.
简单的函数包装器基于上述内容，用于管道输入:
Simple function wrapper based on the above, for use with pipeline input:
filter debug-Chars { [int[]] [char[]] $_ | % { '0x{0:x} [{1}]' -f $_, [char] $_ } }
示例使用:
"vol_01`n" | debug-Chars
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