o(∩_∩)o.dotNet几个函数的"重写"
o(∩_∩)o.dotNet几个函数的"重写"
Project:C#/VB - Automated WebSpider / WebRobot
Author:David Cruwys
using System;namespace Mf.Util
{
/**//// <summary>
/// Summary description for StrUtil.
/// </summary> public class StrUtil { /**//// <summary> Class cannot be instantiated</summary> private StrUtil() { } Left#region Left /**//// <summary> /// Gets the leftmost n characters of a String. If n characters are not /// available, or the String is <code>null</code>, the String will be /// returned without an exception. /// </summary> /// <param name="str">The String to get the leftmost characters from</param> /// <param name="int">The length of the required String</param> /// <returns>The leftmost characters</returns> public static string Left(string str, int len) { if (len < 0 || str == null || str.Length <= len ) { return str; } else { return str.Substring(0, len); } } #endregion LeftIndexOf#region LeftIndexOf /**//// <summary> /// Gets the left most characters starting from the index of <var>search</var> /// <br/> /// If <var>str</var> is <code>null</code>, then <var>str</var> will be returned without an exception. /// <br/><br/> /// If <var>search</var> is not found then <var>str</var> will be returned without an exception. /// </summary> /// <param name="str">The string to get the left most characters off</param> /// <param name="search">The string to search for</param> /// <returns>The left most characters</returns> public static string LeftIndexOf( string str, string search ) { return LeftIndexOf( str, search, 0, false ); } /**//// <summary> /// Gets the left most characters starting from the index of <var>search</var> /// <br/> /// If <var>str</var> is <code>null</code>, then <var>str</var> will be returned without an exception. /// <br/><br/> /// If <var>search</var> is not found then <var>str</var> will be returned without an exception. /// </summary> /// <param name="str">The string to get the left most characters off</param> /// <param name="search">The string to search for</param> /// <param name="includeSearchString">If true will include the search string in the result, if false then the search string is excluded</param> /// <returns>The left most characters</returns> public static string LeftIndexOf( string str, string search, bool includeSearchString ) { return LeftIndexOf( str, search, 0, includeSearchString ); } /**//// <summary> /// Gets the left most characters starting from the index of <var>search</var> /// <br/> /// If <var>str</var> is <code>null</code>, then <var>str</var> will be returned without an exception. /// <br/><br/> /// If <var>search</var> is not found then <var>str</var> will be returned without an exception. /// </summary> /// <param name="str">The string to get the left most characters off</param> /// <param name="search">The string to search for</param> /// <param name="fromIndex">The index to start the search from</param> /// <returns>The left most characters</returns> public static string LeftIndexOf( string str, string search, int fromIndex ) { return LeftIndexOf( str, search, fromIndex, false ); } /**//// <summary> /// Gets the left most characters starting from the index of <var>search</var> /// <br/> /// If <var>str</var> is <code>null</code>, then <var>str</var> will be returned without an exception. /// <br/><br/> /// If <var>search</var> is not found then <var>str</var> will be returned without an exception. /// </summary> /// <param name="str">The string to get the left most characters off</param> /// <param name="search">The string to search for</param> /// <param name="fromIndex">The index to start the search from</param> /// <param name="includeSearchString">If true will include the search string in the result, if false then the search string is excluded</param> /// <returns>The left most characters</returns> public static string LeftIndexOf( string str, string search, int fromIndex, bool includeSearchString ) { if ( Is.EmptyString( str ) || Is.EmptyString( search ) ) { return str; } else { if ( fromIndex > str.Length ) { return str; } int pos = str.IndexOf( search, fromIndex ); if ( pos == -1 ) { return str; } else { return str.Substring( 0, pos + ( includeSearchString ? search.Length : 0 ) ); } } }#endregion LeftOf#region LeftOf /**//// <summary> /// Gets the characters to the left of <var>pos</var>. /// </summary> /// <param name="string">The String to get the left most characters from</param> /// <param name="int">The position to cut from</param> /// <returns>The left most characters</returns> public static string LeftOf(string str, int pos) { if ( str == null ) { return null; } else { if ( pos == -1 ) return ""; if ( pos > str.Length ) return str; return Substring( str, 0, pos ); } } #endregion Right#region Right /**//// <summary> /// Gets the right most n characters of a String. If n characters are not /// available, or the String is <code>null</code>, the String will be /// returned without an exception. /// </summary> /// <param name="str">The String to get the right most characters from</param> /// <param name="int">The length of the required String</param> /// <returns>The right most characters</returns> public static string Right(string str, int len) { if (len < 0 || str == null || str.Length <= len ) { return str; } else { return str.Substring( str.Length - len); } } #endregion RightIndexOf#region RightIndexOf /**//// <summary> /// Gets the right most characters starting from the index of <var>search</var>. /// <br/> /// If <var>str</var> is <code>null</code>, then <var>str</var> will be returned without an exception. /// <br/><br/> /// If <var>search</var> is not found then <var>str</var> will be returned without an exception. /// </summary> /// <param name="str">The string to get the right most characters off</param> /// <param name="search">The string to search for</param> /// <returns>The right most characters</returns> public static string RightIndexOf( string str, string search ) { return RightIndexOf( str, search, 0, false ); } /**//// <summary> /// Gets the right most characters starting from the index of <var>search</var> /// <br/> /// If <var>str</var> is <code>null</code>, then <var>str</var> will be returned without an exception. /// <br/><br/> /// If <var>search</var> is not found then <var>str</var> will be returned without an exception. /// </summary> /// <param name="str">The string to get the right most characters off</param> /// <param name="search">The string to search for</param> /// <param name="includeSearchString">If true will include the search string in the result, if false then the search string is excluded</param> /// <returns>The right most characters</returns> public static string RightIndexOf( string str, string search, bool includeSearchString ) { return RightIndexOf( str, search, 0, includeSearchString ); } /**//// <summary> /// Gets the right most characters starting from the index of <var>search</var> /// <br/> /// If <var>str</var> is <code>null</code>, then <var>str</var> will be returned without an exception. /// <br/><br/> /// If <var>search</var> is not found then <var>str</var> will be returned without an exception. /// </summary> /// <param name="str">The string to get the right most characters off</param> /// <param name="search">The string to search for</param> /// <param name="fromIndex">The index to start the search from</param> /// <returns>The right most characters</returns> public static string RightIndexOf( string str, string search, int fromIndex ) { return RightIndexOf( str, search, fromIndex, false ); } /**//// <summary> /// Gets the right most characters starting from the index of <var>search</var> /// <br/> /// If <var>str</var> is <code>null</code>, then <var>str</var> will be returned without an exception. /// <br/><br/> /// If <var>search</var> is not found then <var>str</var> will be returned without an exception. /// </summary> /// <param name="str">The string to get the right most characters off</param> /// <param name="search">The string to search for</param> /// <param name="fromIndex">The index to start the search from</param> /// <param name="includeSearchString">If true will include the search string in the result, if false then the search string is excluded</param> /// <returns>The right most characters</returns> public static string RightIndexOf( string str, string search, int fromIndex, bool includeSearchString ) { if ( Is.EmptyString( str ) || Is.EmptyString( search ) || fromIndex > str.Length ) { return str; } else { int pos = str.IndexOf( search, fromIndex ); if ( pos == -1 ) { return str; } else { return str.Substring( pos + ( includeSearchString ? 0 : search.Length ) ); } } } #endregion RightLastIndexOf#region RightLastIndexOf /**//// <summary> /// Gets the right most characters starting from the last index of <var>search</var>. /// <br/> /// If the String is <code>null</code>, the String will be returned without an exception. /// <br/><br/> /// If <var>search</var> is not found then <var>str</var> will be returned without an exception. /// </summary> /// <param name="str">The string to get the right most characters off</param> /// <param name="search">The last occurence of search to start from</param> /// <returns>The right most characters</returns> public static string RightLastIndexOf( string str, string search ) { if ( ( str == null ) || (search == null ) ) { return str; } else { int pos = str.LastIndexOf( search ); if ( pos == -1 ) { return str; } else { return str.Substring( pos + search.Length ); } } } #endregion RightOf#region RightOf /**//// <summary> /// Gets the characters to the right of <var>pos</var>. /// </summary> /// <param name="string">The String to get the right most characters from</param> /// <param name="int">The position to cut from</param> /// <returns>The right most characters</returns> public static string RightOf(string str, int pos) { if ( str == null ) { return null; } else { if ( pos == -1 ) { return str; } return Substring( str, pos+1 ); } } #endregion Substring#region Substring /**//// <summary> /// Gets a substring from the specified string avoiding exceptions from invalid start indexes or null strings. /// </summary> /// <param name="str">The String to get the substring from</param> /// <param name="int">The index of the start of the substring</param> /// <returns>substring from start position</returns> public static string Substring(string str, int start) { if ( str == null ) return null; if ( start < 0) start = 0; // Start must be 0 or greater if ( start > str.Length ) return ""; // Start to big return str.Substring( start ); } /**//// <summary> /// Gets a substring from the specified string avoiding exceptions from invalid start indexes, lengths or null strings. /// </summary> /// <param name="string">The String to get the substring from</param> /// <param name="int">The index of the start of the substring</param> /// <param name="int">The number of characters in the substring. </param> /// <returns>substring from start position for <var>length</var> characters</returns> public static string Substring(string str, int start, int length ) { if ( str == null ) return null; if ( start < 0 ) { start = 0; // Start must be 0 or greater } if ( length > str.Length-start ) { length = str.Length-start; } return str.Substring( start, length ); } #endregion StartsWith#region StartsWith /**//// <summary> /// Similer to String.StartsWith except that it is case-insensitive. /// </summary> /// <param name="str">The string to test</param> /// <param name="startsWith">The string to seek</param> /// <returns><b>true</b> if value matches the beginning of this string or is Empty; otherwise <b>false</b></returns> public static bool StartsWith( string str, string startsWith ) { if ( str == null || startsWith == null || startsWith.Length > str.Length ) { return false; } // REFACTOR: Would be quicker to test each character in a loop return str.ToLower( ).StartsWith( startsWith.ToLower( ) ); } #endregion }
}