ASP中的函数应用方法及应用举例(一)

1.Array()
  FUNCTION: Returns a variant containing an array.
  SYNTAX: Array(list)
  ARGUMENTS: list is a comma-delimited list of values to add to the array.
  EXAMPLE: <%
Dim myArray()
For i = 1 to 7
   Redim Preserve myArray(i)
   myArray(i) = WeekdayName(i)
Next
%>
  RESULT: Creates an Array contains 7 elements:
myArray("Sunday","Monday", ... ... "Saturday")
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2. CInt()
  FUNCTION: Returns an expression that has been converted to an Interget subtype.
  SYNTAX: CInt(expression)
  ARGUMENTS: expression is any valid expression
  EXAMPLE: <%
f = "234"
response.write cINT(f) + 2
%>
  RESULT: 236
Converts string "234" to mathematic value 234.
If f is empty (un-initialized variable), cINT() returns 0.
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3. CreateObject()
  FUNCTION: Creates and returns a reference to ActiveX automation object.
  SYNTAX: CreateObject(objName)
  ARGUMENTS: objName is any valid ActiveX automation object.
  EXAMPLE: <%
Set con = Server.CreateObject("ADODB.Connection")
%>
  RESULT:  
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4. CStr()
  FUNCTION: Returns an expression that has been converted to a variant of subtype String.
  SYNTAX: CStr(expression)
  ARGUMENTS: expression is any valid expression
  EXAMPLE: <%
s = 3 + 2
response.write "The result is: " & cStr(s)
%>
  RESULT: Converts a mathematic value 5 to a string "5".
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5. Date()
  FUNCTION: Returns the current system date.
  SYNTAX: Date()
  ARGUMENTS: None.
  EXAMPLE: <%=Date%>
  RESULT: 8/4/99
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6. DateAdd()
  FUNCTION: Returns a date to which a specific time interval has been added.
  SYNTAX: DateAdd(timeinterval,number,date)
  ARGUMENTS: timeinterval is the time interval to add; number is amount of time intervals to add; and date
is the starting date.
  EXAMPLE: <%
currentDate = #8/4/99#
newDate = DateAdd("m",3,currentDate)
response.write newDate
%>

<%
currentDate = #12:34:45 PM#
newDate = DateAdd("h",3,currentDate)
response.write newDate
%>
  RESULT: 11/4/99
3:34:45 PM

"m" = "month";
"d" = "day";

If currentDate is in time format then,
"h" = "hour";
"s" = "second";
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7. DateDiff()
  FUNCTION: Returns the number of intervals between two dates.
  SYNTAX: DateDiff(timeinterval,date1,date2 [, firstdayofweek [, firstweekofyear]])
  ARGUMENTS: timeinterval is the time interval to add; date is a valid date expression; firstdayofweek and
firstweekofyear are optional values to specify the first day of the week and first week of year.
  EXAMPLE: <%
fromDate = #8/4/99#
toDate = #1/1/2000#
response.write "There are " & _
   DateDiff("d",fromDate,toDate) & _
   " days to millenium from 8/4/99."
%>
  RESULT: There are 150 days to millenium from 8/4/99.
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8. Day()
  FUNCTION: Returns a whole number representing the day of the month.
  SYNTAX: Day(date)
  ARGUMENTS: date is any valid date expression.
  EXAMPLE: <%=Day(#8/4/99#)%>
  RESULT: 4
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9. FormatCurrency()
  FUNCTION: Returns an expression formatted as a currency value.
  SYNTAX: FormatCurrency(Expression [, Digit [, LeadingDigit [, Paren [, GroupDigit]]]])
  ARGUMENTS: Expression is a valid numeric expression; Digit is an optional numeric value used to indicate
number of digits to the right of the decimal point; LeadingDigit is an optional tristate value to display
a leading zero; Paren is an optional tristate value used to display parentheses around negative values;
and GroupDigit is an option tristate value used to display a number as specified in the group delimiter
settings of the Control Panel's regional settings.
  EXAMPLE: <%=FormatCurrency(34.3456)%>
  RESULT: $34.35
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10. FormatDateTime()
  FUNCTION: Returns an expression formatted as a date or time.
  SYNTAX: FormatDateTime(Date, [, NamedFormat])
  ARGUMENTS: Date is any valid date expression, and NamedFormat is an optional date/time constant.
  EXAMPLE: <%=FormatDateTime("08/4/99", vbLongDate)%>
  RESULT: Wednesday, August 04, 1999
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10. FormatNumber()
  FUNCTION: Returns an expression formatted as a number.
  SYNTAX: FormatNumber(Expression [, Digit [, LeadingDigit [, Paren [, GroupDigit]]]])
  ARGUMENTS: Expression is a valid numeric expression; Digit is an optional numeric value used to indicate
number of digits to the right of the decimal point; LeadingDigit is an optional tristate value to display
a leading zero; Paren is an optional tristate value used to display parentheses around negative values;
and GroupDigit is an option tristate value used to display a number as specified in the group delimiter
settings of the Control Panel's regional settings.
  EXAMPLE: <%=FormatNumber(45.324567, 3)%>
  RESULT: 45.325
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11. FormatPercent()
  FUNCTION: Returns an expression formatted as a percent value with a trailing percent (%)
  SYNTAX: FormatPercent(Expression [, Digit [, LeadingDigit [, Paren [, GroupDigit]]]])
  ARGUMENTS: Expression is a valid numeric expression; Digit is an optional numeric value used to indicate
number of digits to the right of the decimal point; LeadingDigit is an optional tristate value to display
a leading zero; Paren is an optional tristate value used to display parentheses around negative values;
and GroupDigit is an option tristate value used to display a number as specified in the group delimiter
settings of the Control Panel's regional settings.
  EXAMPLE: <%=FormatPercent(0.45267, 3)%>
  RESULT: 45.267%
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12. Hour()
  FUNCTION: Returns a whole number representing the hour of the day between 0 and 23.
  SYNTAX: Hour(time)
  ARGUMENTS: time is any valid date/time expression.
  EXAMPLE: <%=Hour(#4:45:34 PM#)%>
  RESULT: 16
(Hour has been converted to 24-hour system)
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13. Instr()
  FUNCTION: Returns the numeric position of the first instance of one string within another.
  SYNTAX: Instr([start, ] strToBeSearched, strSearchFor [, compare])
  ARGUMENTS: start (optional) is the numeric position to start the string search; strToBeSearched is the
string expression to be searched; strSearchFor is the string expression search value; and compare
(optional) is the value indicating the comparison constant.
  EXAMPLE: <%
strText = "This is a test!!"
pos = Instr(strText, "a")
response.write pos
%>
  RESULT: 9
(string "a" is the 9th character in strText)
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14. InstrRev()
  FUNCTION: Returns the numeric position of one string within another starting from the end of the string.
  SYNTAX: InstrRev([start, ] strToBeSearched, strSearchFor [, compare])
  ARGUMENTS: start (optional) is the numeric position to start the string search; strToBeSearched is the
string expression to be searched; strSearchFor is the string expression search value; and compare
(optional) is the value indicating the comparison constant.
  EXAMPLE: <%
strText = "This is a test!!"
pos = InstrRev(strText, "s")
response.write pos
%>
  RESULT: 13
(string "s" is the 13th character of strText if you search from the end of the strText)
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15. Int()
  FUNCTION: Returns the integer portion of a number
  SYNTAX: Int(number)
  ARGUMENTS: number is any valid numeric expression.
  EXAMPLE: <%=INT(32.89)%>
  RESULT: 32
(If cINT() is used instead, the result will be 33)
  
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16. IsArray()
  FUNCTION: Returns a boolean value indicating whether a variable is an array.
  SYNTAX: IsArray(name)
  ARGUMENTS: name is the variable to be determined.
  EXAMPLE: <%
strTest = "Test!"
response.write IsArray(strTest)
%>
  RESULT: False
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17. IsDate()
  FUNCTION: Returns a boolean value indicating whether the expression can be converted to a date.
  SYNTAX: IsDate(expression)
  ARGUMENTS: expression is any valid expression.
  EXAMPLE: <%
strTest = "8/4/99"
response.write IsDate(strTest)
%>
  RESULT: True
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18. IsEmpty()
  FUNCTION: Returns a boolean value indicating whether a variable has been initialized.
  SYNTAX: IsEmpty(expression)
  ARGUMENTS: expression is any valid expression.
  EXAMPLE: <%
Dim i
response.write IsEmpty(i)
%>
  RESULT: True
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19. IsNull()
  FUNCTION: Returns a boolean value that indicates whether an expression contains no valid datatype.
  SYNTAX: IsNull(expression)
  ARGUMENTS: expression is any valid expression.
  EXAMPLE: <%
Dim i
response.write IsNull(i)
%>
  RESULT: False
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20. IsNumeric()
  FUNCTION: Returns a boolean value indicating whether an expression can be evaluated as a number.
  SYNTAX: IsNumeric(expression)
  ARGUMENTS: expression is any valid expression.
  EXAMPLE: <%
i = "345"
response.write IsNumeric(i)
%>
  RESULT: True
(Even if there are quotation marks around 345, which indicates datatype of string, IsNumeric() function
will still try to convert a string to numeric value first)
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