2.5 Data Type

MCMD handles plain text files in CSV format, where the data is a sequence of characters. Thus, it depends on how the specific command interprets the character string for the data type. For example, the data in field specified at f= in msum command is converted from a character string to a number. As shown in Table 2.1, MCMD can handle six types of data including numeric, character string, date, time, boolean and vector type.

Table 2.1: Six data types supported by MCMD

Data type	Notation of CSV Data type	Details of Conversion
Numerical type	10, 2.5, 1.5E+10	Convert value to a double-precision real number
Character string type	abc, あいう	Process CSV data as it is
Date type	20130920	Convert 8-digit fixed length string to Gregorian calendar object
Time type	20130920151154, 151154	Convert 6 digit or the 14-digit fixed length string to Gregorian calendar + POSIX time object
Boolean type	1,0	Convert character to boolean value. "1" is true and “0” is false
Vector type	a c b, 1 5 11	Character string delimited by space can be converted to any data type above.

Further, list of data types of commonly used commands is shown in Table 2.2.

Table 2.2: Data types of commonly used commands

Data type	Command	Details
Numerical type	msum	Calculate total of numeric field
	msim	Calculate the similarity between two fields
String type	mjoin	Combine fields from the reference file
	mcombi	Enumerate combination
Date type	age function of mcal	Calculate Age
	leapyear function of mcal	Determine leap year
Time type	now function of mcal	Output the current time
	diffminute function of mcal	Calculate the time difference in minutes
Boolean type	and function of mcal	Compute the logical product
	if function of mcal	Set the value of the criteria
ベクトル型	mvsort	Sort vector elements
	mvuniq	Extract unique vector elements