Learning Objectives
Math Functions
Conversion Functions String Functions
Date and Time Functions Array Functions
Misc. Functions
Math Functions
Abs(vNumber) - Returns the absolute value of a specified number Atn(vNumber) - Returns the arctangent of a specified number Cos(vNumber) - Returns the cosine of a specified number (angle) Exp(vPower) - Returns e raised to a power
Hex(vNumber) - Returns the hexadecimal value of a specified number Int(vNumber) - Returns the integer part of a specified number
Fix(vNumber) - Returns the integer part of a specified number
Log(vNumber) - Returns the natural logarithm of a specified number Oct(vNumber) - Returns the octal value of a specified number
Rnd() - Returns a random number less than 1 but greater or equal to 0
Sgn(vNumber) - Returns an integer that indicates the sign of a specified number Sin(vNumber) - Returns the sine of a specified number (angle)
Sqr(vNumber) - Returns the square root of a specified number Tan(vNumber) - Returns the tangent of a specified number (angle)
Conversion Functions
CBool(vVariant) - Converts an expression to a variant of subtype Boolean CByte(vVariant) - Converts an expression to a variant of subtype Byte CCur(vVariant) - Converts an expression to a variant of subtype Currency
CDate(vVariant) - Converts a valid date and time expression to the variant of subtype Date CDbl(vVariant) - Converts an expression to a variant of subtype Double
CInt(vVariant) - Converts an expression to a variant of subtype Integer CLng(vVariant) - Converts an expression to a variant of subtype Long CSng(vVariant) - Converts an expression to a variant of subtype Single CStr(vVariant) - Converts an expression to a variant of subtype String
String Functions
InStr(sString, sSubString) - Returns the position of the first occurrence of one string within another. The search begins at the first character of the string
InStrRev(sString, sSubString) - Returns the position of the first occurrence of one string within another. The search begins at the last character of the string
LCase(sString) - Converts a specified string to lowercase
Left(sString, iLen) - Returns a specified number of characters from the left side of a string Len(sString) - Returns the number of characters in a string
LTrim(sString) - Removes spaces on the left side of a string RTrim(sString) - Removes spaces on the right side of a string
Trim(sString) - Removes spaces on both the left and the right side of a string Mid(sString, iStart, iLen) - Returns a specified number of characters from a string
Replace(sString, sOld, sNew) - Replaces a specified part of a string with another string a specified number of times
Right(sString) - Returns a specified number of characters from the right side of a string Space(iLen) - Returns a string that consists of a specified number of spaces
StrComp(sString1, sString2) - Compares two strings and returns a value that represents the result of the comparison
String(iLen, sChar, iLen) - Returns a string that contains a repeating character of a specified length
StrReverse(sString) - Reverses a string
UCase(sString) - Converts a specified string to uppercase Asc(sString) - Converts the first letter in a string to ANSI code Chr(iInteger) - Converts the specified ANSI code to a character Date and Time Functions
CDate(vVariant) - Converts a valid date and time expression to the variant of subtype Date Date() - Returns the current system date
DateAdd(sType, iInterval, tDate) - Returns a date to which a specified time interval has been added
DateDiff(tDate1, tDate2) - Returns the number of intervals between two dates DatePart(sType, tDate) - Returns the specified part of a given date
DateSerial(iYear, iMonth, iDate) - Returns the date for a specified year, month, and day DateValue(vVariant) - Returns a date
Day(tDate) - Returns a number that represents the day of the month (between 1 and 31, inclusive)
FormatDateTime(tDate, iType) - Returns an expression formatted as a date or time
Hour(tDate) - Returns a number that represents the hour of the day (between 0 and 23, inclusive)
IsDate(vVariant) - Returns a Boolean value that indicates if the evaluated expression can be converted to a date
Minute(tDate) - Returns a number that represents the minute of the hour (between 0 and 59, inclusive)
Month(tDate) - Returns a number that represents the month of the year (between 1 and 12, inclusive)
MonthName(iMonth) - Returns the name of a specified month Now() - Returns the current system date and time
Second(tDate0 - Returns a number that represents the second of the minute (between 0 and 59, inclusive)
Time() - Returns the current system time
Timer() - Returns the number of seconds since 12:00 AM
TimeSerial(iHour, iMinute, iSecond) - Returns the time for a specific hour, minute, and second
TimeValue(tDate) Returns a time
Weekday(tDate) - Returns a number that represents the day of the week (between 1 and 7, inclusive)
WeekdayName(iWeekDay) - Returns the weekday name of a specified day of the week Year(tDate) - Returns a number that represents the year
Array Functions
Array(vArg1, vArg2, ...) - Returns a variant containing an array
IsArray(vVariant) - Returns a Boolean value that indicates whether a specified variable is an array
Join(aArray) - Returns a string that consists of a number of substrings in an array
LBound(aArray) - Returns the smallest subscript for the indicated dimension of an array Split(sString, sDelimiter) - Returns a zero-based, one-dimensional array that contains a specified number of substrings
UBound(aArray) - Returns the largest subscript for the indicated dimension of an array
Misc. Functions
IsArray(variable) - Returns True if the specified variable is an array
IsDate(variable) - Returns True if the specified variable can be converted to a date IsEmpty(variable) - Returns True if the specified variable is Empty
IsNull(variable) - Returns True is the specified variable is Null
IsNumeric(variable) - Returns True if the specified variable can be converted to a number IsObject(variable) - Returns True if the specified variable is an object
TypeName(variable) - Returns the type name of the specified variable VarType(vVariant) - Returns the type code of the specified variable
Exercises
Print input datatype, and message false if string data.
Generate a unique value, where the value should contain present system date and time. Print Number of times the letter “i” if displayed in the word “Mississippi”.
Session15: Inspecting Variables Received in Procedures
Learning Objectives
This Session provides tutorial examples and notes on inspecting variables received in procedures. Topics include why variables received must be inspected before using them, guidelines on how to inspect variables, crash-free code example to convert anything into a Long integer.
Variable Inspection - Data Type Validation
Variable Inspection - Data Type Validation
If are writing a procedure, and receiving a variable from the calling code through an argument, you cannot always assume that value of the variable is of certain subtype. If you code your procedure with some assumptions, your code will crash if the calling code fails to meet those assumptions. To better protect your code, you want to inspect the value first, and write your code based on the result of the inspection. Variable inspection can be performed at 3 different levels:
1. Determine the structure type of the variable. Is it an object, array, or scalar.
2. Determine the data subtype of the variable. If it is an object, check its properties; If it is an array, check its elements; If it is a scalar, check the subtype of the value: Byte, Integer, Long, Single, Double, Date, Currency, Boolean, or String.
3. Determine the status of the data. Is it Empty or Null.
VBScript offers a number of built-in functions to help you to inspect a variable: IsObject(variable) - Returns True if the specified variable is an object IsArray(variable) - Returns True if the specified variable is an array
IsDate(variable) - Returns True if the specified variable can be converted to a date IsEmpty(variable) - Returns True if the specified variable is Empty
IsNull(variable) - Returns True is the specified variable is Null
IsNumeric(variable) - Returns True if the specified variable can be converted to a number TypeName(variable) - Returns the type name of the specified variable
SubType(variable) - Returns the subtype code of the specified variable Code:
Example: IsObject Set x=Nothing Msgbox IsObject(x) Out Put: True
y="apple"
Out Put: False Example: IsArray
Days=Array("Sun","Mon","Tue","Wed","Thu","Fri","Sat")
Msgbox IsArray(Days) Out Put: True
Monday=1
Msgbox IsArray(Monday) Out Put: False
Example: IsDate
Date_Today="01/01/2000" Msgbox IsDate(Date_Today) Out Put: True
Date_Today="01\01\2000" Msgbox IsDate(Date_Today) Out Put: False