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SECTION 7. STANDARD EXTENSIONS

format codes for each type of data (i.e., character strings, logical, integer, or real) are

given in Table 7.8 and described below.

Character data If the table column contains a character string (with TFORMn =

'rA') then the TFORMn format code must be 'Aw' where w is the number of characters

to display. If the character datum has length less than or equal to w, it is represented

on output right-justified in a string of w characters. If the character datum has length

greater than w, the first w characters of the datum are represented on output in a string

of w characters. Character data are not surrounded by single or double quotation marks

unless those marks are themselves part of the data value.

Logical data If the table column contains logical data (with TFORMn = 'rL') then

the TFORMn format code must be 'Lw' where w is the width in characters of the display

field. Logical data are represented on output with the character T for true or F for false

right-justified in a space-filled string of w characters. A null value may be represented

by a string of w space characters.

Integer data  If the table column contains integer data (with TFORMn = 'rX', 'rB',

'rI', 'rJ', or 'rK') then the TFORMn format code may have any of these forms: Iw.m,

Bw.m, Ow.m, orZw.m. The default value of m is one and the `.m' is optional. The first

letter of the code specifies the number base for the encoding with I for decimal (10),

B for binary (2), O for octal (8), and Z for hexadecimal (16). Hexadecimal format uses

the upper-case letters A through F to represent decimal values 10 through 15. The

output field consists of w characters containing zero or more leading spaces followed by

a minus sign if the internal datum is negative (only in the case of decimal encoding with

the I format code) followed by the magnitude of the internal datum in the form of an

unsigned integer constant in the specified number base with only as many leading zeros

as are needed to have at least m numeric digits. Note that m ≤ w is allowed if all values

are positive, but m < w is required if any values are negative. If the number of digits

required to represent the integer datum exceeds w, then the output field consists of a

string of w asterisk (*) characters.

Real data  If the table column contains real data (with TFORMn = 'rE', or 'rD')

or contains integer data (with any of the TFORMn format codes listed in the previous

paragraph) which are recommended to be displayed as real values (i.e., especially in cases

where the integer values represent scaled physical values using Eq. 7.1), then the TFORMn

format code may have any of these forms: Fw.d, Ew.dEe, Dw.dEe, ENw.d, or ESw.d. In

all cases, the output is a string of w characters including the decimal point, any sign

characters, and any exponent including the exponent's indicators, signs, and values. If

the number of digits required to represent the real datum exceeds w, then the output

FITS Standard