Delphi XE4 TStringHelper用法详解

2024-02-01 16:40•css•阅读 512

原文地址：Delphi XE4 TStringHelper用法详解作者：天下为公

Delphi XE4的TStringHelper，对操作字符串进一步带来更多的方法，估计XE5还能继续用到。

System.SysUtils.TStringHelper

大小写转换:

--------------------------------------------------------------------------------

function ToLower: string;

function ToLower(LocaleID: TLocaleID): string;

function ToLowerInvariant: string;

function ToUpper: string;

function ToUpper(LocaleID: TLocaleID): string;

function ToUpperInvariant: string;

class function LowerCase(const S: string): string;

class function LowerCase(const S: string; LocaleOptions: TLocaleOptions): string;

class function UpperCase(const S: string): string;

class function UpperCase(const S: string; LocaleOptions: TLocaleOptions): string;

//--------------------------------------------------------------------------------

var

str: string;

begin

str := 'Delphi';

str := str.ToLower; // delphi

str := str.ToUpper; // DELPHI

end;

--------------------------------------------------------------------------------

清除两边空格或指定字符:

--------------------------------------------------------------------------------

function Trim: string;

function TrimLeft: string;

function TrimRight: string;

function Trim(const TrimChars: array of Char): string;

function TrimLeft(const TrimChars: array of Char): string;

function TrimRight(const TrimChars: array of Char): string;

//--------------------------------------------------------------------------------

var

str1, str2: string;

begin

str1 := ' Delphi 10000 ';

str2 := str1.TrimLeft; // 'Delphi 10000 '

str2 := str1.TrimRight; // ' Delphi 10000'

str2 := str1.Trim; // 'Delphi 10000'

str2 := str1.Trim([' ', '0']); // 'Delphi 1'

end;

--------------------------------------------------------------------------------

字符串对比:

--------------------------------------------------------------------------------

function CompareTo(const strB: string): Integer;

class function Compare(const StrA: string; const StrB: string): Integer;

class function CompareText(const StrA: string; const StrB: string): Integer;

class function Compare(const StrA: string; const StrB: string; LocaleID: TLocaleID): Integer;

class function Compare(const StrA: string; const StrB: string; IgnoreCase: Boolean): Integer;

class function Compare(const StrA: string; const StrB: string; IgnoreCase: Boolean; LocaleID: TLocaleID): Integer;

class function Compare(const StrA: string; IndexA: Integer; const StrB: string; IndexB: Integer; Length: Integer): Integer;

class function Compare(const StrA: string; IndexA: Integer; const StrB: string; IndexB: Integer; Length: Integer; LocaleID: TLocaleID): Integer;

class function Compare(const StrA: string; IndexA: Integer; const StrB: string; IndexB: Integer; Length: Integer; IgnoreCase: Boolean): Integer;

class function Compare(const StrA: string; IndexA: Integer; const StrB: string; IndexB: Integer; Length: Integer; IgnoreCase: Boolean; LocaleID: TLocaleID): Integer;

class function CompareOrdinal(const StrA: string; const StrB: string): Integer;

class function CompareOrdinal(const StrA: string; IndexA: Integer; const StrB: string; IndexB: Integer; Length: Integer): Integer;

//--------------------------------------------------------------------------------

var

str1, str2: string;

n: Integer;

begin

str1 := 'ABC 123';

str2 := 'abc 123';

n := str1.CompareTo(str2); // -32

n := str1.Compare(str1, str2); // 1

n := str1.CompareText(str1, str2); // 0; 相同

n := str1.Compare(str1, str2, True); // 0; 不区分大小写

n := str1.CompareOrdinal(str1, str2); // -32

n := str1.Compare(str1, 4, str2, 4, 3); // 0; 只对比后三位

end;

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搜索字符串:

--------------------------------------------------------------------------------

function IndexOf(value: Char): Integer;

function IndexOf(const Value: string): Integer;

function IndexOf(Value: Char; StartIndex: Integer): Integer;

function IndexOf(const Value: string; StartIndex: Integer): Integer;

function IndexOf(Value: Char; StartIndex: Integer; Count: Integer): Integer;

function IndexOf(const Value: string; StartIndex: Integer; Count: Integer): Integer;

function IndexOfAny(const AnyOf: array of Char): Integer;

function IndexOfAny(const AnyOf: array of Char; StartIndex: Integer): Integer;

function IndexOfAny(const AnyOf: array of Char; StartIndex: Integer; Count: Integer): Integer;

function LastIndexOf(Value: Char): Integer;

function LastIndexOf(const Value: string): Integer;

function LastIndexOf(Value: Char; StartIndex: Integer): Integer;

function LastIndexOf(const Value: string; StartIndex: Integer): Integer;

function LastIndexOf(Value: Char; StartIndex: Integer; Count: Integer): Integer;

function LastIndexOf(const Value: string; StartIndex: Integer; Count: Integer): Integer;

function LastIndexOfAny(const AnyOf: array of Char): Integer;

function LastIndexOfAny(const AnyOf: array of Char; StartIndex: Integer): Integer;

function LastIndexOfAny(const AnyOf: array of Char; StartIndex: Integer; Count: Integer): Integer;

//--------------------------------------------------------------------------------

var

str: string;

n: Integer;

begin

str := 'A1 A2 A3 A4';

n := str.IndexOf('A'); // 0

n := str.LastIndexOf('A'); // 9

n := str.IndexOf('B'); // -1; 没找到

n := str.IndexOf('A', 1, str.Length - 1); // 3

n := str.LastIndexOf('A', str.Length - 1, str.Length - 1); // 9

n := str.IndexOfAny(['1', '2', '3', '4']); // 1

n := str.LastIndexOfAny(['1', '2', '3', '4']); // 10

end;

--------------------------------------------------------------------------------

是否包含:

--------------------------------------------------------------------------------

function Contains(const Value: string): Boolean;

function StartsWith(const Value: string): Boolean;

function StartsWith(const Value: string; IgnoreCase: Boolean): Boolean;

function EndsWith(const Value: string): Boolean;

function EndsWith(const Value: string; IgnoreCase: Boolean): Boolean;

class function EndsText(const ASubText, AText: string): Boolean;

//--------------------------------------------------------------------------------

var

str: string;

b: Boolean;

begin

str := 'Delphi XE4';

b := str.Contains('XE'); // True

b := str.Contains('xe'); // False

b := str.StartsWith('delphi'); // False

b := str.StartsWith('delphi', True); // True

b := str.EndsWith('XE4'); // True

b := str.EndsText('xe4', str); // True

end;

--------------------------------------------------------------------------------

添加或解除引号:

--------------------------------------------------------------------------------

function QuotedString: string;

function QuotedString(const QuoteChar: Char): string;

function DeQuotedString: string;

function DeQuotedString(const QuoteChar: Char): string;

//--------------------------------------------------------------------------------

var

str1, str2: string;

begin

str1 := 'Delphi';

str2 := str1.QuotedString; // 'Delphi'

str2 := str1.QuotedString('"'); // "Delphi"

str1 := '"Delphi"';

str2 := str1.DeQuotedString('"'); // Delphi

end;

--------------------------------------------------------------------------------

适宽处理:

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function PadLeft(TotalWidth: Integer): string;

function PadLeft(TotalWidth: Integer; PaddingChar: Char): string;

function PadRight(TotalWidth: Integer): string;

function PadRight(TotalWidth: Integer; PaddingChar: Char): string;

//--------------------------------------------------------------------------------

var

str: string;

begin

str := '1';

str := str.PadLeft(4, '0'); // 0001

end;

--------------------------------------------------------------------------------

插入与删除:

--------------------------------------------------------------------------------

function Insert(StartIndex: Integer; const Value: string): string;

function Remove(StartIndex: Integer): string;

function Remove(StartIndex: Integer; Count: Integer): string;

//--------------------------------------------------------------------------------

var

str1, str2: string;

begin

str1 := 'Delphi 4';

str2 := str1.Insert(7, 'XE'); // Delphi XE4

str1 := 'Delphi XE4';

str2 := str1.Remove(6); // Delphi

str2 := str1.Remove(7, 2); // Delphi 4

end;

--------------------------------------------------------------------------------

截取:

--------------------------------------------------------------------------------

function Substring(StartIndex: Integer): string;

function Substring(StartIndex: Integer; Length: Integer): string;

//--------------------------------------------------------------------------------

var

str1, str2: string;

begin

str1 := 'Delphi XE4';

str2 := str1.Substring(7); // XE4

str2 := str1.Substring(7, 2); // XE

end;

--------------------------------------------------------------------------------

替换:

--------------------------------------------------------------------------------

function Replace(OldChar: Char; NewChar: Char): string;

function Replace(OldChar: Char; NewChar: Char; ReplaceFlags: TReplaceFlags): string;

function Replace(const OldValue: string; const NewValue: string): string;

function Replace(const OldValue: string; const NewValue: string; ReplaceFlags: TReplaceFlags): string;

//--------------------------------------------------------------------------------

var

str1, str2: string;

begin

str1 := 'ABC ABC ABC';

str2 := str1.Replace('A', '*'); // *BC *BC *BC

str2 := str1.Replace('A', '*', [rfIgnoreCase]); // *BC ABC ABC

end;

--------------------------------------------------------------------------------

分割:

--------------------------------------------------------------------------------

function Split(const Separator: array of Char): TArray;

function Split(const Separator: array of Char; Count: Integer): TArray;

function Split(const Separator: array of Char; Options: TStringSplitOptions): TArray;

function Split(const Separator: array of string; Options: TStringSplitOptions): TArray;

function Split(const Separator: array of Char; Count: Integer; Options: TStringSplitOptions): TArray;

function Split(const Separator: array of string; Count: Integer; Options: TStringSplitOptions): TArray;

//--------------------------------------------------------------------------------

var

str: string;

arr: TArray;

begin

str := 'A-1,B-2,,,C-3,D-4';

arr := str.Split([',']); // arr[0] = A-1; Length(arr) = 6

arr := str.Split([','], TStringSplitOptions.ExcludeEmpty); // 忽略空项; Length(arr) = 4

arr := str.Split([','], 2); // 只提取前 2

arr := str.Split([',', '-'], ExcludeEmpty); //arr[0] = A; Length(arr) = 8

arr := str.Split([',,,'], None); // 分隔符可以是一个字符串数组

end;

--------------------------------------------------------------------------------

连接:

--------------------------------------------------------------------------------

class function Join(const Separator: string; const values: array of const): string;

class function Join(const Separator: string; const Values: array of string): string;

class function Join(const Separator: string; const Values: IEnumerator): string;

class function Join(const Separator: string; const Values: IEnumerable): string;

class function Join(const Separator: string; const value: array of string; StartIndex: Integer; Count: Integer): string;

//--------------------------------------------------------------------------------

var

S: string;

str: string;

strArr: TArray;

begin

str := 'A1,B2,C3,,,,D4,E5,F6,G7';

strArr := str.Split([','], ExcludeEmpty);

str := S.Join('-', strArr); // A1-B2-C3-D4-E5-F6-G7

str := S.Join('; ', [1,2,3,4,5]); // 1; 2; 3; 4; 5

str := S.Join(',', ['abc', 123, true]); // abc,123,True

end;

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类型转换:

--------------------------------------------------------------------------------

function ToBoolean: Boolean;

function ToInteger: Integer;

function ToSingle: Single;

function ToDouble: Double;

function ToExtended: Extended;

class function ToBoolean(const S: string): Boolean;

class function ToInteger(const S: string): Integer;

class function ToSingle(const S: string): Single;

class function ToDouble(const S: string): Double;

class function ToExtended(const S: string): Extended;

class function Parse(const Value: Integer): string;

class function Parse(const Value: Int64): string;

class function Parse(const Value: Boolean): string;

class function Parse(const Value: Extended): string;

//--------------------------------------------------------------------------------

var

S: string;

str: string;

n: Integer;

b: Boolean;

f: Double;

begin

str := S.Parse(123);

n := str.ToInteger; // 123

b := str.ToBoolean; // True

str := S.Parse(True);

b := str.ToBoolean; // True

n := str.ToInteger; // -1

str := S.Parse(3.14159260000);

f := str.ToDouble; //3.1415926

end;

--------------------------------------------------------------------------------

定界符:

--------------------------------------------------------------------------------

function IsDelimiter(const Delimiters: string; Index: Integer): Boolean;

function LastDelimiter(const Delims: string): Integer;

//--------------------------------------------------------------------------------

var

str: string;

b: Boolean;

n: Integer;

begin

str := 'http://del.cnblogs.com';

b := str.IsDelimiter(':', 4); // True

b := str.IsDelimiter('//', 5); // True

n := str.LastDelimiter('.'); // 18

n := str.IndexOf('.'); // 10

end;

--------------------------------------------------------------------------------

空字符串:

--------------------------------------------------------------------------------

const Empty = '';

function IsEmpty: Boolean;

class function IsNullOrEmpty(const Value: string): Boolean;

class function IsNullOrWhiteSpace(const Value: string): Boolean;

//--------------------------------------------------------------------------------

var

S: string;

str: string;

b: Boolean;

begin

str := ' ';

b := str.IsEmpty; // False

b := S.IsNullOrWhiteSpace(str); // True

end;

--------------------------------------------------------------------------------

String 与 Char:

--------------------------------------------------------------------------------

class function Create(C: Char; Count: Integer): string;

class function Create(const Value: array of Char; StartIndex: Integer; Length: Integer): string;

class function Create(const Value: array of Char): string;

property Chars[Index: Integer]: Char read GetChars;

property Length: Integer read GetLength;

function CountChar(const C: Char): Integer;

function ToCharArray: TArray;

function ToCharArray(StartIndex: Integer; Length: Integer): TArray;

procedure CopyTo(SourceIndex: Integer; var destination: array of Char; DestinationIndex: Integer; Count: Integer);

//--------------------------------------------------------------------------------

var

S: string;

str, str2: string;

charArr: TCharArray;

n: Integer;

c: Char;

begin

str := 'ABC';

n := str.Length; // 3

c := str.Chars[0]; // A = str[1]

str := S.Create('A', 7); // AAAAAAA

charArr := 'ABCDEFG'.ToCharArray;

str := s.Create(charArr); // ABCDEFG

str := S.Create(charArr, 1, 3); // BCD

charArr := '1234567890'.ToCharArray;

str := 'ABCDEFG';

str.CopyTo(1, charArr, 2, 3);

str := S.Create(charArr); // 12BCD67890

end;

--------------------------------------------------------------------------------

其他:

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function Equals(const Value: string): Boolean;

function GetHashCode: Integer;

class function Equals(const a: string; const b: string): Boolean;

class function Format(const Format: string; const args: array of const): string;

class function Copy(const Str: string): string;

//--------------------------------------------------------------------------------

// 用 Equals 不如直接用 = 号

// 用 Copy 不如直接用 :=

// 用 string.Format 不如直接用 Format()

// 总之, 还是有用处的多!

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Delphi XE4 TStringHelper用法详解

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