给定字符串“ThisStringHasNoSpacesButItDoesHaveCapitals”，什么是在大写字母之前添加空格的最好方法。所以结尾字符串是"This string Has No space But It Does Have大写"
下面是我使用正则表达式的尝试
System.Text.RegularExpressions.Regex.Replace(value, "[A-Z]", " $0")
当前回答
对于任何正在寻找回答这个问题的c++函数的人，您可以使用下面的方法。这是模仿@Binary Worrier给出的答案。这种方法只是自动保留首字母缩略词。
using namespace std;
void AddSpacesToSentence(string& testString)
stringstream ss;
ss << testString.at(0);
for (auto it = testString.begin() + 1; it != testString.end(); ++it )
{
int index = it - testString.begin();
char c = (*it);
if (isupper(c))
{
char prev = testString.at(index - 1);
if (isupper(prev))
{
if (index < testString.length() - 1)
{
char next = testString.at(index + 1);
if (!isupper(next) && next != ' ')
{
ss << ' ';
}
}
}
else if (islower(prev))
{
ss << ' ';
}
}
ss << c;
}
cout << ss.str() << endl;
我为这个函数使用的测试字符串，结果是:
"helloWorld" -> "helloWorld" "HelloWorld" -> "HelloWorld" "HelloABCWorld" -> "HelloABCWorld" "HelloWorldABC" -> "HelloWorldABC" "ABCHelloWorld" -> "ABCHelloWorld" " abc hello world " -> " abc hello world " " abchelloworld " -> " abchelloworld " " a " -> " a "
其他回答
下面是在SQL中如何做到这一点
create FUNCTION dbo.PascalCaseWithSpace(@pInput AS VARCHAR(MAX)) RETURNS VARCHAR(MAX)
BEGIN
declare @output varchar(8000)
set @output = ''
Declare @vInputLength INT
Declare @vIndex INT
Declare @vCount INT
Declare @PrevLetter varchar(50)
SET @PrevLetter = ''
SET @vCount = 0
SET @vIndex = 1
SET @vInputLength = LEN(@pInput)
WHILE @vIndex <= @vInputLength
BEGIN
IF ASCII(SUBSTRING(@pInput, @vIndex, 1)) = ASCII(Upper(SUBSTRING(@pInput, @vIndex, 1)))
begin
if(@PrevLetter != '' and ASCII(@PrevLetter) = ASCII(Lower(@PrevLetter)))
SET @output = @output + ' ' + SUBSTRING(@pInput, @vIndex, 1)
else
SET @output = @output + SUBSTRING(@pInput, @vIndex, 1)
end
else
begin
SET @output = @output + SUBSTRING(@pInput, @vIndex, 1)
end
set @PrevLetter = SUBSTRING(@pInput, @vIndex, 1)
SET @vIndex = @vIndex + 1
END
return @output
END
欢迎来到Unicode
所有这些解决方案对于现代文本来说本质上都是错误的。你需要使用能理解大小写的东西。由于Bob要求使用其他语言，我将为Perl提供两种语言。
我提供了四种解决方案，从最坏到最好。只有最好的人才是对的。其他人都有问题。下面是一个测试运行，向您展示什么可行，什么不可行，以及在哪里。我用了下划线，这样你们就能看到空格放在了哪里，我把所有错的地方都标记了出来。
Testing TheLoneRanger
Worst: The_Lone_Ranger
Ok: The_Lone_Ranger
Better: The_Lone_Ranger
Best: The_Lone_Ranger
Testing MountMᶜKinleyNationalPark
[WRONG] Worst: Mount_MᶜKinley_National_Park
[WRONG] Ok: Mount_MᶜKinley_National_Park
[WRONG] Better: Mount_MᶜKinley_National_Park
Best: Mount_Mᶜ_Kinley_National_Park
Testing ElÁlamoTejano
[WRONG] Worst: ElÁlamo_Tejano
Ok: El_Álamo_Tejano
Better: El_Álamo_Tejano
Best: El_Álamo_Tejano
Testing TheÆvarArnfjörðBjarmason
[WRONG] Worst: TheÆvar_ArnfjörðBjarmason
Ok: The_Ævar_Arnfjörð_Bjarmason
Better: The_Ævar_Arnfjörð_Bjarmason
Best: The_Ævar_Arnfjörð_Bjarmason
Testing IlCaffèMacchiato
[WRONG] Worst: Il_CaffèMacchiato
Ok: Il_Caffè_Macchiato
Better: Il_Caffè_Macchiato
Best: Il_Caffè_Macchiato
Testing MisterDženanLjubović
[WRONG] Worst: MisterDženanLjubović
[WRONG] Ok: MisterDženanLjubović
Better: Mister_Dženan_Ljubović
Best: Mister_Dženan_Ljubović
Testing OleKingHenryⅧ
[WRONG] Worst: Ole_King_HenryⅧ
[WRONG] Ok: Ole_King_HenryⅧ
[WRONG] Better: Ole_King_HenryⅧ
Best: Ole_King_Henry_Ⅷ
Testing CarlosⅤºElEmperador
[WRONG] Worst: CarlosⅤºEl_Emperador
[WRONG] Ok: CarlosⅤº_El_Emperador
[WRONG] Better: CarlosⅤº_El_Emperador
Best: Carlos_Ⅴº_El_Emperador
顺便说一下，这里几乎所有人都选择了第一种方式，即标记为“最差”的方式。少数人选择了标记为“OK”的第二种方式。但是在我之前没有人告诉过你如何做“更好”或“最好”的方法。
下面是带有四个方法的测试程序:
#!/usr/bin/env perl
use utf8;
use strict;
use warnings;
# First I'll prove these are fine variable names:
my (
$TheLoneRanger ,
$MountMᶜKinleyNationalPark ,
$ElÁlamoTejano ,
$TheÆvarArnfjörðBjarmason ,
$IlCaffèMacchiato ,
$MisterDženanLjubović ,
$OleKingHenryⅧ ,
$CarlosⅤºElEmperador ,
);
# Now I'll load up some string with those values in them:
my @strings = qw{
TheLoneRanger
MountMᶜKinleyNationalPark
ElÁlamoTejano
TheÆvarArnfjörðBjarmason
IlCaffèMacchiato
MisterDženanLjubović
OleKingHenryⅧ
CarlosⅤºElEmperador
};
my($new, $best, $ok);
my $mask = " %10s %-8s %s\n";
for my $old (@strings) {
print "Testing $old\n";
($best = $old) =~ s/(?<=\p{Lowercase})(?=[\p{Uppercase}\p{Lt}])/_/g;
($new = $old) =~ s/(?<=[a-z])(?=[A-Z])/_/g;
$ok = ($new ne $best) && "[WRONG]";
printf $mask, $ok, "Worst:", $new;
($new = $old) =~ s/(?<=\p{Ll})(?=\p{Lu})/_/g;
$ok = ($new ne $best) && "[WRONG]";
printf $mask, $ok, "Ok:", $new;
($new = $old) =~ s/(?<=\p{Ll})(?=[\p{Lu}\p{Lt}])/_/g;
$ok = ($new ne $best) && "[WRONG]";
printf $mask, $ok, "Better:", $new;
($new = $old) =~ s/(?<=\p{Lowercase})(?=[\p{Uppercase}\p{Lt}])/_/g;
$ok = ($new ne $best) && "[WRONG]";
printf $mask, $ok, "Best:", $new;
}
当你能在这个数据集上得到与“最佳”相同的分数时，你就知道你做对了。在那之前，你还没有。这里没有人比“还行”做得更好，大多数人都做得“最差”。我期待看到有人发布正确的ℂ代码。
我注意到，StackOverflow的高亮代码是悲惨的笨拙再次。他们所做的一切都和这里提到的其他糟糕的方法一样(大部分但不是全部)。难道不是早就该让ASCII停止使用了吗?这已经没有意义了，假装这是你的全部是大错特错的。这会导致糟糕的代码。
你拥有的一切都很完美。只需要记住将value重新赋值给这个函数的返回值即可。
value = System.Text.RegularExpressions.Regex.Replace(value, "[A-Z]", " $0");
在Ruby中，通过Regexp:
"FooBarBaz".gsub(/(?!^)(?=[A-Z])/, ' ') # => "Foo Bar Baz"
受到二元忧虑者答案的启发，我尝试了一下。
结果如下:
/// <summary>
/// String Extension Method
/// Adds white space to strings based on Upper Case Letters
/// </summary>
/// <example>
/// strIn => "HateJPMorgan"
/// preserveAcronyms false => "Hate JP Morgan"
/// preserveAcronyms true => "Hate JPMorgan"
/// </example>
/// <param name="strIn">to evaluate</param>
/// <param name="preserveAcronyms" >determines saving acronyms (Optional => false) </param>
public static string AddSpaces(this string strIn, bool preserveAcronyms = false)
{
if (string.IsNullOrWhiteSpace(strIn))
return String.Empty;
var stringBuilder = new StringBuilder(strIn.Length * 2)
.Append(strIn[0]);
int i;
for (i = 1; i < strIn.Length - 1; i++)
{
var c = strIn[i];
if (Char.IsUpper(c) && (Char.IsLower(strIn[i - 1]) || (preserveAcronyms && Char.IsLower(strIn[i + 1]))))
stringBuilder.Append(' ');
stringBuilder.Append(c);
}
return stringBuilder.Append(strIn[i]).ToString();
}
测试使用秒表运行10000000次迭代和各种字符串长度和组合。
平均比二进制忧虑者的答案快50%(可能多一点)。
