我从古腾堡计划的“威廉莎士比亚全集”开始，这是一个 UTF-8 文本文件，可从http://www.gutenberg.org/ebooks/100 获得。在 PowerShell 中，我跑了
Get-Content -Tail 50 $filename | Sort-Object -CaseSensitive
- 我相信 - 将文件的最后 50 行（即，由换行符分隔的字符串）传送到 Sort-Object，它被配置为按字母顺序排序，字符串以小写字母开头，然后以大写字母开头。
为什么下图中的输出（尤其是 P 中的）没有按照-CaseSensitive 开关排序？什么是解决方案？
【问题讨论】：
标签： powershell sorting output
注意：此答案侧重于对 整个字符串 进行排序的一般情况（按 所有 个字符，而不仅仅是按 first em> 一个）。
您正在寻找 ordinal 排序，其中字符按 Unicode 代码点按数字排序（ “ASCII 值”），因此 所有大写字母，作为一个组，排在所有小写字母之前。
从 Windows PowerShell v5.1 / PowerShell Core v7.0 开始，Sort-Object 总是使用词法排序[1 ]（默认使用 invariant 区域性，但可以使用 -Culture 参数更改），其中 区分大小写的排序 仅表示 给定字母的小写形式直接在其大写形式之前，并非所有字母统称为；例如，b 在B 之前排序，但它们都在a 和A 之后（此外，逻辑与序数大小写相反，它是大写 字母第一）：
PS> 'B', 'b', 'A', 'a' | Sort-Object -CaseSensitive
a
A
b
B
有一个解决方法，但是，它 (a) 将大写字母排在小写字母之前，并且 (b) 以牺牲性能为代价：
Sort-Object 以支持序数排序。# PSv4+ syntax
# Note: Uppercase letters come first.
PS> 'B', 'b', 'A', 'a' |
Sort-Object { -join ([int[]] $_.ToCharArray()).ForEach('ToString', 'x4') }
A
B
a
b
解决方案将每个输入字符串映射到由 4 位十六进制组成的字符串。字符代码点的表示，例如'aB'变成'00610042'，分别代表代码点0x61和0x42；比较这些表示就相当于按字符的代码点对字符串进行排序。
# Get the last 50 lines as a list.
[Collections.Generic.List[string]] $lines = Get-Content -Tail 50 $filename
# Sort the list in place, using ordinal sorting
$lines.Sort([StringComparer]::Ordinal)
# Output the result.
# Note that uppercase letters come first.
$lines
[StringComparer]::Ordinal 返回一个实现[System.Collections.IComparer] 接口的对象。
在管道中使用此解决方案是可能的，但需要通过管道将行数组作为单个对象发送，-ReadCount 参数提供：
Get-Content -Tail 50 $filename -ReadCount 0 | ForEach-Object {
($lines = [Collections.Generic.List[string]] $_).Sort([StringComparer]::Ordinal)
$lines # output the sorted lines
}
注意：如上所述，这排序大写字母第一。
要对所有小写字母进行排序首先，您需要通过[System.Comparison[string]]委托实现自定义排序，这在PowerShell中可以被实现为一个脚本块（{ ... }），它接受两个输入字符串并返回它们的排序等级（-1（或任何负值）代表小于，0代表等于，1（或任何正值）大于）：
$lines.Sort({ param([string]$x, [string]$y)
# Determine the shorter of the two lengths.
$count = if ($x.Length -lt $y.Length) { $x.Length } else { $y.Length }
# Loop over all characters in corresponding positions.
for ($i = 0; $i -lt $count; ++$i) {
if ([char]::IsLower($x[$i]) -ne [char]::IsLower($y[$i])) {
# Sort all lowercase chars. before uppercase ones.
return (1, -1)[[char]::IsLower($x[$i])]
} elseif ($x[$i] -ne $y[$i]) { # compare code points (numerically)
return $x[$i] - $y[$i]
}
# So far the two strings compared equal, continue.
}
# The strings compared equal in all corresponding character positions,
# so the difference in length, if any, is the decider (longer strings sort
# after shorter ones).
return $x.Length - $y.Length
})
注意：对于 英文 文本，上述内容应该可以正常工作，但为了支持所有可能包含代理代码单元对和不同规范化形式（组合重音字符与分解重音字符）的 Unicode 文本，还需要做更多的工作。
[1] 在 Windows 上，默认执行所谓的单词排序：“某些非字母数字字符可能具有分配给它们的特殊权重。例如，连字符 (-) 可能分配给它的权重非常小，因此coop 和co-op 在排序列表中彼此相邻出现。";在 Unix 类平台上，字符串排序 是默认设置，其中没有特殊权重适用于非字母数字字符。 - 见the docs。
【讨论】：
获得所需结果的一种方法是获取每个字符串的第一个字符并将其转换为Int，这将为您提供该字符的 ASCII 代码，然后您可以按数字排序为所需的顺序。
Get-Content -Tail 50 $filename | Sort-Object -Property @{E={[int]$_[0]};Ascending=$true}
我们可以使用sort-object 的-property 参数创建一个表达式，我们使用[int] 转换为int，然后使用$_ 抓取第一个字符以获取管道中的当前字符串/行然后[0] 获取该字符串中的第一个字符并按升序对其进行排序。
这提供了以下输出。
您可能希望从输出中删除空白，但我将由您决定。
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更新
先对小写进行排序，然后修剪空白行。本质上，我只是将 ascii 数字乘以任意数量，以便在数字上高于小写对应数字。
在示例文本中，没有任何行以特殊字符或标点符号开头，这可能需要修改以正确处理这些情况。
Get-Content -Tail 50 $filename | ? { -not [string]::IsNullOrEmpty($_) } | Sort-Object -Property {
if($_[0] -cmatch "[A-Z]")
{
5*[int]$_[0]
}
else
{
[int]$_[0]
}
}
这将输出：
against accepting unsolicited donations from donors in such states who
approach us with offers to donate.
considerable effort, much paperwork and many fees to meet and keep up
concept of a library of electronic works that could be freely shared
editions, all of which are confirmed as not protected by copyright in
how to make donations to the Project Gutenberg Literary Archive
have not met the solicitation requirements, we know of no prohibition
including checks, online payments and credit card donations. To donate,
methods and addresses. Donations are accepted in a number of other ways
necessarily keep eBooks in compliance with any particular paper edition.
our email newsletter to hear about new eBooks.
please visit: www.gutenberg.org/donate
statements concerning tax treatment of donations received from outside
the U.S. unless a copyright notice is included. Thus, we do not
the United States. U.S. laws alone swamp our small staff.
visit www.gutenberg.org/donate
with these requirements. We do not solicit donations in locations where
works.
www.gutenberg.org
with anyone. For forty years, he produced and distributed Project
we have not received written confirmation of compliance. To SEND
DONATIONS or determine the status of compliance for any particular state
Foundation, how to help produce our new eBooks, and how to subscribe to
Gutenberg-tm eBooks with only a loose network of volunteer support.
International donations are gratefully accepted, but we cannot make any
Most people start at our Web site which has the main PG search facility:
Please check the Project Gutenberg Web pages for current donation
Professor Michael S. Hart was the originator of the Project Gutenberg-tm
Project Gutenberg-tm eBooks are often created from several printed
Section 5. General Information About Project Gutenberg-tm electronic
This Web site includes information about Project Gutenberg-tm, including
While we cannot and do not solicit contributions from states where we
【讨论】：
比较 Jacob 和 mklement0 的响应，Jacob 的解决方案具有视觉简单、直观、使用管道以及可扩展到按第一个单词的第二个字符或第二个单词的第一个字符等排序的优点。mklement0 的解决方案具有更快的优势，并让我了解如何排序小写然后大写。
下面我想分享我对 Jacob 解决方案的扩展，它按第二个单词的第一个字符排序。对于莎士比亚全集不是特别有用，但对于逗号分隔的表格非常有用。
Function Replace-Nulls($line) {
$dump_var = @(
if ( !($line) ) {
$line = [char]0 + " " + [char]0 + " [THIS WAS A LINE OF NULL WHITESPACE]"
} # End if
if ( !(($line.split())[1]) ) {
$line += " " + [char]8 + " [THIS WAS A LINE WITH ONE WORD AND THE REST NULL WHITESPACE]"
} # End if
) # End definition of dump_var
return $line
} # End Replace-Nulls
echo "."
$cleaned_output = Get-Content -Tail 20 $filename | ForEach-Object{ Replace-Nulls($_) }
$cleaned_output | Sort-Object -Property {[int]((($_).split())[1])[0]}
【讨论】：
Sort-Object 肯定会按输入字符串中的 all 字符排序，而不仅仅是 first 一。仅按第一个字母排序让我觉得这是一个奇特的用例。我建议不要发布此答案，而是将您对其他两个答案的对比转移到您的 question 中，并完全省略代码 sn-p，因为它是您提出的问题的附带问题，可能只是分散注意力给未来的读者。
Sort-Object 才能提供一个很好的解决方案。