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")
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
仅由ASCII字符组成的输入字符串的c#解决方案。regex结合了反向回溯来忽略出现在字符串开头的大写字母。使用Regex.Replace()返回所需的字符串。
参见regex101.com演示。
using System;
using System.Text.RegularExpressions;
public class RegexExample
{
public static void Main()
{
var text = "ThisStringHasNoSpacesButItDoesHaveCapitals";
// Use negative lookbehind to match all capital letters
// that do not appear at the beginning of the string.
var pattern = "(?<!^)([A-Z])";
var rgx = new Regex(pattern);
var result = rgx.Replace(text, " $1");
Console.WriteLine("Input: [{0}]\nOutput: [{1}]", text, result);
}
}
预期的输出:
Input: [ThisStringHasNoSpacesButItDoesHaveCapitals]
Output: [This String Has No Spaces But It Does Have Capitals]
更新:这里有一个变种,也将处理首字母缩写(大写字母序列)。
参见regex101.com演示和ideone.com演示。
using System;
using System.Text.RegularExpressions;
public class RegexExample
{
public static void Main()
{
var text = "ThisStringHasNoSpacesASCIIButItDoesHaveCapitalsLINQ";
// Use positive lookbehind to locate all upper-case letters
// that are preceded by a lower-case letter.
var patternPart1 = "(?<=[a-z])([A-Z])";
// Used positive lookbehind and lookahead to locate all
// upper-case letters that are preceded by an upper-case
// letter and followed by a lower-case letter.
var patternPart2 = "(?<=[A-Z])([A-Z])(?=[a-z])";
var pattern = patternPart1 + "|" + patternPart2;
var rgx = new Regex(pattern);
var result = rgx.Replace(text, " $1$2");
Console.WriteLine("Input: [{0}]\nOutput: [{1}]", text, result);
}
}
预期的输出:
Input: [ThisStringHasNoSpacesASCIIButItDoesHaveCapitalsLINQ]
Output: [This String Has No Spaces ASCII But It Does Have Capitals LINQ]
其他回答
这是我的:
private string SplitCamelCase(string s)
{
Regex upperCaseRegex = new Regex(@"[A-Z]{1}[a-z]*");
MatchCollection matches = upperCaseRegex.Matches(s);
List<string> words = new List<string>();
foreach (Match match in matches)
{
words.Add(match.Value);
}
return String.Join(" ", words.ToArray());
}
在Ruby中,通过Regexp:
"FooBarBaz".gsub(/(?!^)(?=[A-Z])/, ' ') # => "Foo Bar Baz"
这个正则表达式在每个大写字母前放置一个空格字符:
using System.Text.RegularExpressions;
const string myStringWithoutSpaces = "ThisIsAStringWithoutSpaces";
var myStringWithSpaces = Regex.Replace(myStringWithoutSpaces, "([A-Z])([a-z]*)", " $1$2");
注意前面的空间,如果“$1$2”,这是可以完成的。
结果如下:
"This Is A String Without Spaces"
仅由ASCII字符组成的输入字符串的c#解决方案。regex结合了反向回溯来忽略出现在字符串开头的大写字母。使用Regex.Replace()返回所需的字符串。
参见regex101.com演示。
using System;
using System.Text.RegularExpressions;
public class RegexExample
{
public static void Main()
{
var text = "ThisStringHasNoSpacesButItDoesHaveCapitals";
// Use negative lookbehind to match all capital letters
// that do not appear at the beginning of the string.
var pattern = "(?<!^)([A-Z])";
var rgx = new Regex(pattern);
var result = rgx.Replace(text, " $1");
Console.WriteLine("Input: [{0}]\nOutput: [{1}]", text, result);
}
}
预期的输出:
Input: [ThisStringHasNoSpacesButItDoesHaveCapitals]
Output: [This String Has No Spaces But It Does Have Capitals]
更新:这里有一个变种,也将处理首字母缩写(大写字母序列)。
参见regex101.com演示和ideone.com演示。
using System;
using System.Text.RegularExpressions;
public class RegexExample
{
public static void Main()
{
var text = "ThisStringHasNoSpacesASCIIButItDoesHaveCapitalsLINQ";
// Use positive lookbehind to locate all upper-case letters
// that are preceded by a lower-case letter.
var patternPart1 = "(?<=[a-z])([A-Z])";
// Used positive lookbehind and lookahead to locate all
// upper-case letters that are preceded by an upper-case
// letter and followed by a lower-case letter.
var patternPart2 = "(?<=[A-Z])([A-Z])(?=[a-z])";
var pattern = patternPart1 + "|" + patternPart2;
var rgx = new Regex(pattern);
var result = rgx.Replace(text, " $1$2");
Console.WriteLine("Input: [{0}]\nOutput: [{1}]", text, result);
}
}
预期的输出:
Input: [ThisStringHasNoSpacesASCIIButItDoesHaveCapitalsLINQ]
Output: [This String Has No Spaces ASCII But It Does Have Capitals LINQ]
以下是我的解决方案,基于Binary Worriers的建议和Richard Priddys的评论,但也考虑到空白可能存在于提供的字符串中,所以它不会在现有空白旁边添加空白。
public string AddSpacesBeforeUpperCase(string nonSpacedString)
{
if (string.IsNullOrEmpty(nonSpacedString))
return string.Empty;
StringBuilder newText = new StringBuilder(nonSpacedString.Length * 2);
newText.Append(nonSpacedString[0]);
for (int i = 1; i < nonSpacedString.Length; i++)
{
char currentChar = nonSpacedString[i];
// If it is whitespace, we do not need to add another next to it
if(char.IsWhiteSpace(currentChar))
{
continue;
}
char previousChar = nonSpacedString[i - 1];
char nextChar = i < nonSpacedString.Length - 1 ? nonSpacedString[i + 1] : nonSpacedString[i];
if (char.IsUpper(currentChar) && !char.IsWhiteSpace(nextChar)
&& !(char.IsUpper(previousChar) && char.IsUpper(nextChar)))
{
newText.Append(' ');
}
else if (i < nonSpacedString.Length)
{
if (char.IsUpper(currentChar) && !char.IsWhiteSpace(nextChar) && !char.IsUpper(nextChar))
{
newText.Append(' ');
}
}
newText.Append(currentChar);
}
return newText.ToString();
}