The following lines were added (+) and removed (-):
== Asc (function) ==== Functions and Description == === Asc (function) ===== Chr (function) ===== Chr (function) ===== InStr (function) ===== InStr (function) ===== InStrRev (function) ===== InStrRev (function) ===Returns the position of an occurrence of one string within another, from the end of string.New in VB6. Similar to InStr but searches from end of string. Returns the position of an occurrence of one string within another, from the end of string.== Mid (function) ===== Join (function) ===New in VB6 Used to join arrays elements. === Mid (function) ===== StrComp (function) ===== Replace (function) ===New in VB6. Returns a string in which a specified substring has been replaced with another substring a specified number of times. Syntax:Replace(expression, find, replace[, start[, count[, compare]]]) Example Debug.print Replace("abababa", "a", "") Example public Function StripOut(From as string, What as string) as string Dim i as Integer StripOut = From for i = 1 to len(What) StripOut = Replace(StripOut, mid$(What, i, 1), "") next i End Function === Reverse (function) ===New in VB6. To reverse a string. === Split (function) ===New in VB6 Split a string into a variant array. === StrComp (function) ===== Performance Rating ==table 1{| class="stylish"|+ Relative performance of VB6 string functions|-! Function! Performance! Description|-| Len| class="num" | 1| Len(S) returns the number of ''characters'' in string S.<br />''(Note: works differently with UDTs)''|-| LenB| class="num" | 1| LenB(S) returns the number of ''bytes'' in S.|-| AscW| class="num" | 1| AscW(S) returns the ''Unicode value'' of the first character in S.|-| AscB| class="num" | 1| AscB(S) returns the ''first byte'' in S.|-| Asc| class="num" | 7| Asc(S) returns the ''ANSI value'' of the first character in S.|-| ChrW$| class="num" | 17| ChrW$(U) returns a string containing the ''Unicode character'' U.|-| ChrB$| class="num" | 18| ChrB$(B) returns a ''byte string'' containing the ''character'' B.|-| Chr$| class="num" | 24| Chr$(A) returns a string containing the ''ANSI character'' A.|-| Left$| class="num" | 18| Left$(S,x) returns x characters from the ''start'' of S.|-| Right$| class="num" | 21| Right$(S,x) returns x characters from the ''end'' of S.|-| Mid$| class="num" | 24| Mid$(S,x,y) returns y characters from S, starting at the ''x'th'' character.|-| CStr| class="num" | 36| CStr(x) returns the string representation of x (localized).|-| Str$| class="num" | 111| Str$(x) returns the string representation of x (not localized).|}How to read the table: Calling Len takes 1 unit of time, while Asc takes 7 units. You can call Len 7 times in the same time you call Asc once.table 2<TABLE CLASS="stylish"><CAPTION>Relative performance of VB6 string functions</CAPTION><TR><TH>Function</TH><TH>Performance</TH><TH>Description</TH></TR><TR><TD>LTrim$</TD><TD CLASS="num">20</TD><TD>LTrim$(S) returns a copy of S without <EM>leading</EM> spaces.</TD></TR><TR><TD>RTrim$</TD><TD CLASS="num">21</TD><TD>RTrim$(S) returns a copy of S without <EM>trailing</EM> spaces.</TD></TR><TR><TD>Trim$</TD><TD CLASS="num">29</TD><TD>Trim$(S) returns a copy of S without <EM>leading or trailing</EM> spaces.</TD></TR><TR><TD>Val</TD><TD CLASS="num">89</TD><TD>Val(S) returns the numeric value contained in S (non-localized).</TD></TR><TR><TD>CInt</TD><TD CLASS="num">81</TD><TD>CInt(S) returns the integer value contained in S (localized, rounded).</TD></TR><TR><TD>CDbl</TD><TD CLASS="num">103</TD><TD>CDbl(S) returns the double floating point value contained in S (localized).</TD></TR><TR><TD>LCase$</TD><TD CLASS="num">53</TD><TD>LCase$(S) returns a copy of S with <EM>lower case letters</EM>.</TD></TR><TR><TD>UCase$</TD><TD CLASS="num">53</TD><TD>UCase$(S) returns a copy of S with <EM>upper case letters</EM>.</TD></TR><TR><TD>StrConv(vbLowerCase)</TD><TD CLASS="num">327</TD><TD>StrConv(S,vbLowerCase) returns a copy of S with <EM>lower case letters</EM>.</TD></TR><TR><TD>StrConv(vbUpperCase)</TD><TD CLASS="num">333</TD><TD>StrConv(S,vbUpperCase) returns a copy of S with <EM>upper case letters</EM>.</TD></TR><TR><TD>StrComp(vbBinaryCompare)</TD><TD CLASS="num">47</TD><TD>StrComp(S1,S2,vbBinaryCompare) compares string S1 and S2 based on their <EM>Unicode values</EM>.</TD></TR><TR><TD>StrComp(vbTextCompare)</TD><TD CLASS="num">65</TD><TD>StrComp(S1,S2,vbTextCompare) compares string S1 and S2 in a <EM>locale-dependent, case-insensitive way</EM>.</TD></TR><TR><TD>InStr(vbBinaryCompare)</TD><TD CLASS="num">14</TD><TD>InStr(x,S1,S2,vbBinaryCompare) looks for S2 in S1, starting at position x, in a <EM>locale-independent, case-sensitive way</EM>.</TD></TR><TR><TD>InStr(vbTextCompare)</TD><TD CLASS="num">156</TD><TD>InStr(x,S1,S2,vbTextCompare) looks for S2 in S1, starting at position x, using <A HREF="instr.html#vbtextcompare">text comparison</A>.</TD></TR><TR><TD><b style="color:black;background-color:#a0ffff">InStrRev</b>(vbBinaryCompare)</TD><TD CLASS="num">69</TD><TD><b style="color:black;background-color:#a0ffff">InStrRev</b>(S1,S2,x,vbBinaryCompare) looks for S2 in S1, from position x back to 1, in a <EM>locale-independent, case-sensitive way</EM>.</TD></TR><TR><TD><b style="color:black;background-color:#a0ffff">InStrRev</b>(vbTextCompare)</TD><TD CLASS="num">193</TD><TD><b style="color:black;background-color:#a0ffff">InStrRev</b>(S1,S2,x,vbTextCompare) looks for S2 in S1, from position x back to 1, using <A HREF="instr.html#vbtextcompare">text comparison</A>.</TD></TR><TR><TD><b style="color:black;background-color:#99ff99">Replace</b>(vbBinaryCompare)</TD><TD CLASS="num">375</TD><TD><b style="color:black;background-color:#99ff99">Replace</b>(S1,S2,S3,x,y,vbBinaryCompare) replaces S2 with S3 in S1, starting at position x, max y times, in a <EM>locale-independent, case-sensitive way</EM>.</TD></TR><TR><TD><b style="color:black;background-color:#99ff99">Replace</b>(vbTextCompare)</TD><TD CLASS="num">513</TD><TD><b style="color:black;background-color:#99ff99">Replace</b>(S1,S2,S3,x,y,vbBinaryCompare) replaces S2 with S3 in S1, starting at position x, max y times, using <EM>text comparison</EM>.</TD></TR></TABLE>Reference: http://www.aivosto.com/vbtips/stringopt2.html == Null, 0, and Empty Strings ==In VB, Null is a subtype of a Variant, in the same way the Empty is also. In other words, Null and Empty are both special states of a Variant variable.vbNull and vbEmpty are the codes returned from the VarType function when applied to a value of that type, e.g. VarType(Empty) = vbEmpty VarType(Null) = vbNullThis provides one method of testing whether a value is Null or Empty. The other is by calling the IsNull and IsEmpty functions.In a database, NULL has a similar status to Null is VB Variants, althoughit's defined by the SQL standard rather than the VB language.Use the NULL keyword to assign Null to a recordset field, use the IsNull function to test if a recordset fields contains Null.* '''vbNullString''': The same as "", as in an empty string. It is more efficient to use vbNullString though. use it instead of ""* '''vbNull''': This is supposed to be NULL but actually equals 1.* '''vbNullChar''': * '''Null''': Used for writing NULL, however, will appear as a 0 in a database numeric field after write.* '''Empty''': Also appears as a 0 in a database numeric field after write.* '''Nothing''': === The Differences among Empty, Nothing, vbNull, vbNullChar, vbNullString and the Zero-Length String ===quoted from somewhere: '''""''': A zero-length string (commonly called an "empty string") is technically a zero-length BSTR that actually uses six bytes of memory. In general, you should use the constant vbNullString instead, particularly when calling external DLL procedures.'''Empty''': A variant of VarType 0 (vbEmpty) that has not yet been initialized. Test whether it is "nil" using the IsEmpty function.'''Nothing''': Destroys an object reference using the Set statement. Test whether it is "nil" using the Is operator:If obj Is Nothing Then...'''Null''': A variant of VarType 1 (vbNull) that means "no valid data" and generally indicates a database field with no value. Don't confuse this with a C NULL, which indicates zero. Test whether it is "nil" using the IsNull function.'''vbNullChar''': A character having a value of zero. It is commonly used for adding a C NULL to a string or for filling a fixed-length string with zeroes:Path = String(255, vbNullChar)'''vbNullString''': A string having a value of zero, such as a C NULL, that takes no memory. Use this string for calling external procedures looking for a null pointer to a string. To distinguish between vbNullString and "", use the VBA StrPtr function: StrPtr(vbNullString) is zero, while StrPtr("") is a nonzero memory address. [Note: the StrPtr() function may not be a part of the VBA members shown in the Object Browser so it will not AutoComplete. Enter the following line in the Immediate Window to determine if this function is available: ?StrPtr(vbNullString). This should return 0 immediately.]