Implementing String.Format() in VB6
有关VB6字符串操作性能的良好资源:http://www.aivosto.com/vbtips/stringopt2.html
关于一个不相关的问题,我还想出了几个字符串比较函数,请在CodeReview.SE上找到它们
这些功能对于提高VB6的可读性非常有用,特别是如果您最近被.net代码所困扰,突然突然需要进入VB6代码库中……请尽情享受!
我在任何地方都找不到,所以我做了一个自己的:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 | Public PADDING_CHAR As String Public Function StringFormat(format_string As String, ParamArray values()) As String 'VB6 implementation of .net String.Format(), slightly customized. 'Tested with Office 2010 VBA (x64) Dim return_value As String Dim values_count As Integer 'some error-handling constants: Const ERR_FORMAT_EXCEPTION As Long = vbObjectError Or 9001 Const ERR_ARGUMENT_NULL_EXCEPTION As Long = vbObjectError Or 9002 Const ERR_SOURCE As String ="StringFormat" Const ERR_MSG_INVALID_FORMAT_STRING As String ="Invalid format string." Const ERR_MSG_FORMAT_EXCEPTION As String ="The number indicating an argument to format is less than zero, or greater than or equal to the length of the args array." 'use SPACE as default padding character If PADDING_CHAR = vbNullString Then PADDING_CHAR = Chr$(32) 'figure out number of passed values: values_count = UBound(values) + 1 Dim regex As RegExp Dim matches As MatchCollection Dim thisMatch As Match Dim thisString As String Dim thisFormat As String 'when format_string starts with"@", escapes are not replaced '(string is treated as a literal string with placeholders) Dim useLiteral As Boolean Dim escapeHex As Boolean 'indicates whether HEX specifier"0x" is to be escaped or not 'validate string_format: Set regex = New RegExp regex.Pattern ="{({{)*(\\w+)(,-?\\d+)?(:[^}]+)?}(}})*" regex.IgnoreCase = True regex.Global = True Set matches = regex.Execute(format_string) 'determine if values_count matches number of unique regex matches: Dim uniqueCount As Integer Dim tmpCSV As String For Each thisMatch In matches If Not StringContains(tmpCSV, thisMatch.SubMatches(1)) Then uniqueCount = uniqueCount + 1 tmpCSV = tmpCSV & thisMatch.SubMatches(1) &"," End If Next 'unique indices count must match values_count: If matches.Count > 0 And uniqueCount <> values_count Then _ Err.Raise ERR_FORMAT_EXCEPTION, _ ERR_SOURCE, ERR_MSG_FORMAT_EXCEPTION useLiteral = StringStartsWith("@", format_string) 'remove the"@" literal specifier If useLiteral Then format_string = Right(format_string, Len(format_string) - 1) If Not useLiteral And StringContains(format_string,"\\\") Then _ format_string = Replace(format_string,"\\\", Chr$(27)) If StringContains(format_string,"\\\") Then _ format_string = Replace(format_string,"\\\", Chr$(27)) If matches.Count = 0 And format_string <> vbNullString And UBound(values) = -1 Then 'only format_string was specified: skip to checking escape sequences: return_value = format_string GoTo checkEscapes ElseIf UBound(values) = -1 And matches.Count > 0 Then Err.Raise ERR_ARGUMENT_NULL_EXCEPTION, _ ERR_SOURCE, ERR_MSG_FORMAT_EXCEPTION End If return_value = format_string 'dissect format_string: Dim i As Integer, v As String, p As String 'i: iterator; v: value; p: placeholder Dim alignmentGroup As String, alignmentSpecifier As String Dim formattedValue As String, alignmentPadding As Integer 'iterate regex matches (each match is a placeholder): For i = 0 To matches.Count - 1 'get the placeholder specified index: Set thisMatch = matches(i) p = thisMatch.SubMatches(1) 'if specified index (0-based) > uniqueCount (1-based), something's wrong: If p > uniqueCount - 1 Then _ Err.Raise ERR_FORMAT_EXCEPTION, _ ERR_SOURCE, ERR_MSG_FORMAT_EXCEPTION v = values(p) 'get the alignment specifier if it is specified: alignmentGroup = thisMatch.SubMatches(2) If alignmentGroup <> vbNullString Then _ alignmentSpecifier = Right$(alignmentGroup, LenB(alignmentGroup) / 2 - 1) 'get the format specifier if it is specified: thisString = thisMatch.Value If StringContains(thisString,":") Then Dim formatGroup As String, precisionSpecifier As Integer Dim formatSpecifier As String, precisionString As String 'get the string between":" and"}": formatGroup = Mid$(thisString, InStr(1, thisString,":") + 1, (LenB(thisString) / 2) - 2) formatGroup = Left$(formatGroup, LenB(formatGroup) / 2 - 1) precisionString = Right$(formatGroup, LenB(formatGroup) / 2 - 1) formatSpecifier = Mid$(thisString, InStr(1, thisString,":") + 1, 1) 'applicable formatting depends on the type of the value (yes, GOTO!!): If TypeName(values(p)) ="Date" Then GoTo DateTimeFormatSpecifiers If v = vbNullString Then GoTo ApplyStringFormat NumberFormatSpecifiers: If precisionString <> vbNullString And Not IsNumeric(precisionString) Then _ Err.Raise ERR_FORMAT_EXCEPTION, _ ERR_SOURCE, ERR_MSG_INVALID_FORMAT_STRING If precisionString = vbNullString Then precisionString = 0 Select Case formatSpecifier Case"C","c" 'CURRENCY format, formats string as currency. 'Precision specifier determines number of decimal digits. 'This implementation ignores regional settings '(hard-coded group separator, decimal separator and currency sign). precisionSpecifier = CInt(precisionString) thisFormat ="#,##0.$" If LenB(formatGroup) > 2 And precisionSpecifier > 0 Then 'if a non-zero precision is specified... thisFormat = _ Replace$(thisFormat,".","." & String$(precisionString, Chr$(48))) End If Case"D","d" 'DECIMAL format, formats string as integer number. 'Precision specifier determines number of digits in returned string. precisionSpecifier = CInt(precisionString) thisFormat ="0" thisFormat = Right$(String$(precisionSpecifier,"0") & thisFormat, _ IIf(precisionSpecifier = 0, Len(thisFormat), precisionSpecifier)) Case"E","e" 'EXPONENTIAL NOTATION format (aka"Scientific Notation") 'Precision specifier determines number of decimals in returned string. 'This implementation ignores regional settings' '(hard-coded decimal separator). precisionSpecifier = CInt(precisionString) thisFormat ="0.00000#" & formatSpecifier &"-#" 'defaults to 6 decimals If LenB(formatGroup) > 2 And precisionSpecifier > 0 Then 'if a non-zero precision is specified... thisFormat ="0." & String$(precisionSpecifier - 1, Chr$(48)) &"#" & formatSpecifier &"-#" ElseIf LenB(formatGroup) > 2 And precisionSpecifier = 0 Then Err.Raise ERR_FORMAT_EXCEPTION, _ ERR_SOURCE, ERR_MSG_INVALID_FORMAT_STRING End If Case"F","f" 'FIXED-POINT format 'Precision specifier determines number of decimals in returned string. 'This implementation ignores regional settings' '(hard-coded decimal separator). precisionSpecifier = CInt(precisionString) thisFormat ="0" If LenB(formatGroup) > 2 And precisionSpecifier > 0 Then 'if a non-zero precision is specified... thisFormat = (thisFormat &".") & String$(precisionSpecifier, Chr$(48)) Else 'no precision specified - default to 2 decimals: thisFormat ="0.00" End If Case"G","g" 'GENERAL format (recursive) 'returns the shortest of either FIXED-POINT or SCIENTIFIC formats in case of a Double. 'returns DECIMAL format in case of a Integer or Long. Dim eNotation As String, ePower As Integer, specifier As String precisionSpecifier = IIf(CInt(precisionString) > 0, CInt(precisionString), _ IIf(StringContains(v,"."), Len(v) - InStr(1, v,"."), 0)) 'track character case of formatSpecifier: specifier = IIf(formatSpecifier ="G","D","d") If TypeName(values(p)) ="Integer" Or TypeName(values(p)) ="Long" Then 'Integer types: use {0:D} (recursive call): formattedValue = StringFormat("{0:" & specifier &"}", values(p)) ElseIf TypeName(values(p)) ="Double" Then 'Non-integer types: use {0:E} specifier = IIf(formatSpecifier ="G","E","e") 'evaluate the exponential notation value (recursive call): eNotation = StringFormat("{0:" & specifier &"}", v) 'get the power of eNotation: ePower = Mid$(eNotation, InStr(1, UCase$(eNotation),"E-") + 1, Len(eNotation) - InStr(1, UCase$(eNotation),"E-")) If ePower > -5 And Abs(ePower) < precisionSpecifier Then 'use {0:F} when ePower > -5 and abs(ePower) < precisionSpecifier: 'evaluate the floating-point value (recursive call): specifier = IIf(formatSpecifier ="G","F","f") formattedValue = StringFormat("{0:" & formatSpecifier & _ IIf(precisionSpecifier <> 0, precisionString, vbNullString) &"}", values(p)) Else 'fallback to {0:E} if previous rule didn't apply: formattedValue = eNotation End If End If GoTo AlignFormattedValue 'Skip the"ApplyStringFormat" step, it's applied already. Case"N","n" 'NUMERIC format, formats string as an integer or decimal number. 'Precision specifier determines number of decimal digits. 'This implementation ignores regional settings' '(hard-coded group and decimal separators). precisionSpecifier = CInt(precisionString) If LenB(formatGroup) > 2 And precisionSpecifier > 0 Then 'if a non-zero precision is specified... thisFormat ="#,##0" thisFormat = (thisFormat &".") & String$(precisionSpecifier, Chr$(48)) Else 'only the"D" is specified thisFormat ="#,##0" End If Case"P","p" 'PERCENT format. Formats string as a percentage. 'Value is multiplied by 100 and displayed with a percent symbol. 'Precision specifier determines number of decimal digits. thisFormat ="#,##0%" precisionSpecifier = CInt(precisionString) If LenB(formatGroup) > 2 And precisionSpecifier > 0 Then 'if a non-zero precision is specified... thisFormat ="#,##0" thisFormat = (thisFormat &".") & String$(precisionSpecifier, Chr$(48)) Else 'only the"P" is specified thisFormat ="#,##0" End If 'Append the percentage sign to the format string: thisFormat = thisFormat &"%" Case"R","r" 'ROUND-TRIP format (a string that can round-trip to an identical number) 'example: ?StringFormat("{0:R}", 0.0000000001141596325677345362656) ' ...returns"0.000000000114159632567735" 'convert value to a Double (chop off overflow digits): v = CDbl(v) Case"X","x" 'HEX format. Formats a string as a Hexadecimal value. 'Precision specifier determines number of total digits. 'Returned string is prefixed with"&H" to specify Hex. v = Hex(v) precisionSpecifier = CInt(precisionString) If LenB(precisionString) > 0 Then 'precision here stands for left padding v = Right$(String$(precisionSpecifier,"0") & v, IIf(precisionSpecifier = 0, Len(v), precisionSpecifier)) End If 'add C# hex specifier, apply specified casing: '(VB6 hex specifier would cause Format() to reverse the formatting): v ="0x" & IIf(formatSpecifier ="X", UCase$(v), LCase$(v)) Case Else If IsNumeric(formatSpecifier) And val(formatGroup) = 0 Then formatSpecifier = formatGroup v = Format(v, formatGroup) Else Err.Raise ERR_FORMAT_EXCEPTION, _ ERR_SOURCE, ERR_MSG_INVALID_FORMAT_STRING End If End Select GoTo ApplyStringFormat DateTimeFormatSpecifiers: Select Case formatSpecifier Case"c","C" 'CUSTOM date/time format 'let VB Format() parse precision specifier as is: thisFormat = precisionString Case"d" 'SHORT DATE format thisFormat ="ddddd" Case"D" 'LONG DATE format thisFormat ="dddddd" Case"f" 'FULL DATE format (short) thisFormat ="dddddd h:mm AM/PM" Case"F" 'FULL DATE format (long) thisFormat ="dddddd ttttt" Case"g" thisFormat ="ddddd hh:mm AM/PM" Case"G" thisFormat ="ddddd ttttt" Case"s" 'SORTABLE DATETIME format thisFormat ="yyyy-mm-ddThh:mm:ss" Case"t" 'SHORT TIME format thisFormat ="hh:mm AM/PM" Case"T" 'LONG TIME format thisFormat ="ttttt" Case Else Err.Raise ERR_FORMAT_EXCEPTION, _ ERR_SOURCE, ERR_MSG_INVALID_FORMAT_STRING End Select GoTo ApplyStringFormat End If ApplyStringFormat: 'apply computed format string: formattedValue = Format(v, thisFormat) AlignFormattedValue: 'apply specified alignment specifier: If alignmentSpecifier <> vbNullString Then alignmentPadding = Abs(CInt(alignmentSpecifier)) If CInt(alignmentSpecifier) < 0 Then 'negative: left-justified alignment If alignmentPadding - Len(formattedValue) > 0 Then _ formattedValue = formattedValue & _ String$(alignmentPadding - Len(formattedValue), PADDING_CHAR) Else 'positive: right-justified alignment If alignmentPadding - Len(formattedValue) > 0 Then _ formattedValue = String$(alignmentPadding - Len(formattedValue), PADDING_CHAR) & formattedValue End If End If 'Replace C# hex specifier with VB6 hex specifier, 'only if hex specifier was introduced in this function: If (Not useLiteral And escapeHex) And _ StringContains(formattedValue,"0x") Then _ formattedValue = Replace$(formattedValue,"0x","&H") 'replace all occurrences of placeholder {i} with their formatted values: return_value = Replace(return_value, thisString, formattedValue, Count:=1) 'reset before reiterating: thisFormat = vbNullString Next checkEscapes: 'if there's no more backslashes, don't bother checking for the rest: If useLiteral Or Not StringContains(return_value,"\") Then GoTo normalExit Dim escape As New EscapeSequence Dim escapes As New Collection escapes.Add escape.Create("\ ", vbNewLine),"0" escapes.Add escape.Create("\\q", Chr$(34)),"1" escapes.Add escape.Create("\\t", vbTab),"2" escapes.Add escape.Create("\\a", Chr$(7)),"3" escapes.Add escape.Create("\\b", Chr$(8)),"4" escapes.Add escape.Create("\\v", Chr$(13)),"5" escapes.Add escape.Create("\\f", Chr$(14)),"6" escapes.Add escape.Create("\ ", Chr$(15)),"7" For i = 0 To escapes.Count - 1 Set escape = escapes(CStr(i)) If StringContains(return_value, escape.EscapeString) Then _ return_value = Replace(return_value, escape.EscapeString, escape.ReplacementString) If Not StringContains(return_value,"\") Then _ GoTo normalExit Next 'replace"ASCII (oct)" escape sequence Set regex = New RegExp regex.Pattern ="\\\\(\\d{3})" regex.IgnoreCase = True regex.Global = True Set matches = regex.Execute(format_string) Dim char As Long If matches.Count <> 0 Then For Each thisMatch In matches p = thisMatch.SubMatches(0) '"p" contains the octal number representing the ASCII code we're after: p ="&O" & p 'prepend octal prefix char = CLng(p) return_value = Replace(return_value, thisMatch.Value, Chr$(char)) Next End If 'if there's no more backslashes, don't bother checking for the rest: If Not StringContains("\", return_value) Then GoTo normalExit 'replace"ASCII (hex)" escape sequence Set regex = New RegExp regex.Pattern ="\\\\x(\\w{2})" regex.IgnoreCase = True regex.Global = True Set matches = regex.Execute(format_string) If matches.Count <> 0 Then For Each thisMatch In matches p = thisMatch.SubMatches(0) '"p" contains the hex value representing the ASCII code we're after: p ="&H" & p 'prepend hex prefix char = CLng(p) return_value = Replace(return_value, thisMatch.Value, Chr$(char)) Next End If normalExit: Set escapes = Nothing Set escape = Nothing If Not useLiteral And StringContains(return_value, Chr$(27)) Then _ return_value = Replace(return_value, Chr$(27),"\") StringFormat = return_value End Function |
请注意方法签名中的
然后可以像下面这样使用该函数:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | ?StringFormat("(C) Currency: . . . . . . . . {0:C}\ " & _ "(D) Decimal:. . . . . . . . . {0:D}\ " & _ "(E) Scientific: . . . . . . . {1:E}\ " & _ "(F) Fixed point:. . . . . . . {1:F}\ " & _ "(N) Number: . . . . . . . . . {0:N}\ " & _ "(P) Percent:. . . . . . . . . {1:P}\ " & _ "(R) Round-trip: . . . . . . . {1:R}\ " & _ "(X) Hexadecimal:. . . . . . . {0:X}\ ",-123, -123.45) |
输出:
1 2 3 4 5 6 7 8 | (C) Currency: . . . . . . . . -123.00$ (D) Decimal:. . . . . . . . . -123 (E) Scientific: . . . . . . . -1.23450E2 (F) Fixed point:. . . . . . . -123 (N) Number: . . . . . . . . . -123 (P) Percent:. . . . . . . . . -12,345% (R) Round-trip: . . . . . . . -123.45 (X) Hexadecimal:. . . . . . . &HFFFFFF85 |
并且也这样:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | ?StringFormat("(c) Custom format: . . . . . .{0:cYYYY-MM-DD (MMMM)}\ " & _ "(d) Short date: . . . . . . . {0:d}\ " & _ "(D) Long date:. . . . . . . . {0:D}\ " & _ "(T) Long time:. . . . . . . . {0:T}\ " & _ "(f) Full date/short time: . . {0:f}\ " & _ "(F) Full date/long time:. . . {0:F}\ " & _ "(s) Sortable: . . . . . . . . {0:s}\ ", Now()) |
输出:
1 2 3 4 5 6 7 | (c) Custom format: . . . . . .2013-01-26 (January) (d) Short date: . . . . . . . 1/26/2013 (D) Long date:. . . . . . . . Saturday, January 26, 2013 (T) Long time:. . . . . . . . 8:28:11 PM (f) Full date/short time: . . 1/26/2013 8:28:11 PM (F) Full date/long time:. . . Saturday, January 26, 2013 8:28:11 PM (s) Sortable: . . . . . . . . 2013-01-26T20:28:11 |
也可以指定对齐方式(/填充)并使用转义序列:
1 2 3 4 5 6 7 | ?StringFormat ("\\q{0}, {1}!\\x20\ '{2,10:C2}'\ '{2,-10:C2}'","hello","world", 100) "hello, world!" ' 100.00$' '100.00$ ' |
查看http://msdn.microsoft.com/fr-fr/library/b1csw23d(v=vs.80).aspx中的示例,只有少数格式说明符未实现,主要是日期/时间说明符...但是我会认为" c"自定义日期/时间格式说明符可以弥补这一点。
该函数使用
1 2 3 4 | Public Function StringContains(string_source As String, find_text As String, _ Optional ByVal caseSensitive As Boolean = True) As Boolean StringContains = StringContainsAny(string_source, caseSensitive, find_text) End Function |
编辑:此代码现在可以正确处理""转义符,如注释中所述。同样,尽管
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | Public Function StringContainsAny(string_source As String, ByVal caseSensitive As Boolean, _ ParamArray find_values()) As Boolean Dim i As Integer, found As Boolean If caseSensitive Then For i = LBound(find_values) To UBound(find_values) found = (InStr(1, string_source, _ find_values(i), vbBinaryCompare) <> 0) If found Then Exit For Next Else For i = LBound(find_values) To UBound(find_values) StringContainsAny = (InStr(1, LCase$(string_source), _ LCase$(find_values(i)), vbBinaryCompare) <> 0) If found Then Exit For Next End If StringContainsAny = found End Function |
考虑以下:
1 2 3 | foo = Instr(1, source,"value1") > 0 Or Instr(1, source,"value2") > 0 _ Or Instr(1, source,"value3") > 0 Or Instr(1, source,"value4") > 0 _ Or Instr(1, source,"value5") > 0 Or Instr(1, source,"value6") > 0 _ |
在VB可以确定
编辑:以前的编辑几乎消除了转义序列;使用小类" EscapeSequence"公开了两个属性和一种工厂方法,将它们恢复了状态-这样做可以保留for-each循环并处理所有简单的转义,而无需重复很多代码。
此代码还使用
1 2 3 4 5 6 7 8 9 | Public Function StringStartsWith(ByVal find_text As String, ByVal string_source As String, Optional ByVal caseSensitive As Boolean = True) As Boolean If caseSensitive Then StringStartsWith = (Left$(string_source, LenB(find_text) / 2) = find_text) Else StringStartsWith = (Left$(LCase(string_source), LenB(find_text) / 2) = LCase$(find_text)) End If End Function |