PRINTF, 1, names, years, salary, Format= $
'("Name", 28X, "Year", 4X, "Total Salary")'

PRINTF, 1, Format= $
'("Name", 28X, "Year", 4X, "Total Salary")'

PRINT, Format = $
'("The values are: ", 2("<", I1, ">"))', INDGEN(6)

The values are: <0><1>

<2><3>

<4><5>

2("<", I1, ">")

10/20/92 12:00:10.90

21/01/93 11:06:29.0875

10-JAN-1992 12:46

MAR:1993 $25440.0

Use classical programming constructs—With this method, you open the file, loop to read the data, close the file, and run the data through one of the date/time conversion routines. This method is shown below in "Method 1—Read the File with READF".

Use one of the DC_READ routines—With this method, you define one or more variables that use the date/time system structure organization, and then use DC_READ_FIXED or DC_READ_FREE to transfer the data into those variables using date/time templates. This method is shown in "Method 2—Read the File with DC_READ_FIXED".

LAM 10/02/90 09:32:00 10.00 32767

COS 10/02/90 09:36:00 15.89 99999

SNV 10/02/90 09:37:00 14.22 87654

loc = STRARR(3) & calib = LONARR(3)

date1 = STRARR(3) & time1 = STRARR(3)

; Create variables to hold the location, calibration, date, time,

; and decibel level.

decibels = FLTARR(3)

; Open data file for input.

OPENR, 1, 'chrono.dat'

; Define scalar strings and a long integer scalar.

locs = ' ' & date1s = locs & time1s = date1s

calibs = 1L

; Initialize counter.

I = 0

; Loop over each record of data.

WHILE (NOT EOF(1)) DO BEGIN

; Read scalars; the first three are string variables, the 

; fourth is a float, and the fifth one is an integer.

READF, 1, locs, date1s, time1s, decibelss, calibs, Format = $
"(A3, 2(1X, A8), 1X, F5.2, 1X, I5)"

; Store in each vector.

loc(I) = locs & date1(I) = date1s & $ 
time1(I) = time1s & calib(I) = calibs $ 
& decibels(I) = decibelss

; Increment counter and check for too many records.

IF I LE 2 THEN I = I+1 ELSE CLOSE, 1 & $ 
STOP, "Too many records."

ENDWHILE 

; Close the file.

CLOSE, 1

; Use one of the conversion utilities, STR_TO_DT, to convert

; the strings to date/time data. The variable date1 uses 

; Template 1, while the variable time1 uses Template –1. The

; result array, my_dt_arr, holds both the MM/DD/YY and the

; HH:MM:SS data.

my_dt_arr = STR_TO_DT(date1, time1, Date_Fmt=1, Time_Fmt = –1)

LAM 100290 093200 10.00 32767

COS 100290 093600 15.89 99999

SNV 100290 093700 14.22 87654

; Define integer arrays to hold the months, days, years, hours, 

; minutes, and seconds data.

year = INTARR(3) & mon = year & day = year

hour = INTARR(3) & min = hour & sec = hour

; Define integer scalars for use inside the read loop.

years = 0 & mons = 0 & days = 0

hours = 0 & mins = 0 & secs = 0

; Create variables to hold location, calibration, and decibel

; level.

loc = STRARR(3) & calib = LONARR(3)

decibels = FLTARR(3)

; Initialize string and long integer scalars.

locs = ' ' & calibs = 1L

; Open data file for input.

OPENR, 1, 'chrono.dat'

; Initialize counter.

I = 0

; Beginning of read loop.

WHILE NOT EOF(1) DO BEGIN

; Read scalars; first one is a string variable, the next six

; are integer variables, the eighth is a float, and the ninth 

; one is an integer.

READF, 1, locs, mons, days, years, hours, mins, secs, $
decibelss, calibs, Format = $
"(A3, 2(1X, 3(I2)), 1X, F5.2, 1X, I5)"

; Store in each vector.

year(I) = years & mon(I)= mons

day(I) = days & hour(I) = hours

min(I) = mins & sec(I) = secs

; Increment counter and check for too many records.

IF I LE 2 THEN I = I+1 ELSE CLOSE, 1 & $ 
STOP, "Too many records."

ENDWHILE 

CLOSE, 1

; Use one of the conversion utilities, VAR_TO_DT, to convert the 

; variables to date/time format.

my_dt_arr = VAR_TO_DT(year, mon, day, hour, min, sec)

PRINT, my_dt_arr

{ 1990 10 2 9 32 0.00000 86946.397 0 }

{ 1990 10 2 9 36 0.00000 86946.400 0 }

{ 1990 10 2 9 37 0.00000 86946.401 0 }

LAM 10/02/90 09:32:00 10.00 32767

COS 10/02/90 09:36:00 15.89 99999

SNV 10/02/90 09:37:00 14.22 87654

; The system structure definition of date/time is !DT. Date/time 

; variables must be defined as !DT structure arrays before being

; used if the date/time data is to be read as such.

date1 = REPLICATE({!DT},3)

; Explicitly define string, integer, and floating-point vectors.

loc = STRARR(3) & calib = LONARR(3)

decibels = FLTARR(3)

; DC_READ_FIXED handles the opening and closing of the file.

; It transfers the values in “chrono.dat” to the variables in the

; variable list, working from left to right. The variable date1

; appears in the variable list twice, once to read the date data

; and once to read the time data.

status = DC_READ_FIXED("chrono.dat", loc, date1, date1, $
decibels, calib, /Column, Format="%s %8s %8s %f %d", $
Dt_Template=[1,-1])

Figure 9-3: Sample Data File

; Open data file for input.

OPENR, 1, 'bullwinkle.wp'

; Create variables to hold the name, number of years, and monthly

; salaries. Each variable’s type is automatically determined by

; the type of initial value it is given.

name = '' & years = 0 & salary = FLTARR(12)

; Output a heading for the summary.

PRINT, 'Name      Years      Yearly Salary'

; Output a ruling line for the heading.

PRINT, '--------------------------------------------'

; Loop over each employee.

WHILE (NOT EOF(1)) DO BEGIN

; Read the data on the next employee.

READF, 1, name, years, salary, $
Format = "(A16, I3, 2(/, 6F10.2))"

; Output the employee information. Use the TOTAL function

; to compute the yearly salaries from the monthly salaries.

PRINT, Format = "(A16, I5, 5X, F10.2)",$ 
name, years, TOTAL(salary)

ENDWHILE

CLOSE, 1

Figure 9-4: Organized Table Structure

; Create variables to hold the name, number of years, and monthly

; salaries.

name = STRARR(4) & years = INTARR(4)

salary = FLTARR(12, 4)

; DC_READ_FIXED handles the opening and closing of the file. It

; transfers values in “bullwinkle.wp” to variables in the 

; variable list, working from left to right. The two slashes in 

; the format string force DC_READ_FIXED to switch to a new record 

; in the input file. When reading row-oriented data, each vari

; able is “filled up” before any data is transferred to the next 

; variable in the variable list. The value of the Ignore keyword 

; insures that all blank lines are skipped instead of being 

; interpreted as data.

status = DC_READ_FIXED('bullwinkle.wp', name, years, salary, $
Format= "(4A16, " + "/, I3, 3(10X,I3), /, 48(F7.2, 3X))", $
Ignore=["$BLANK_LINES"])

; Print a heading and ruling line for the heading.

PRINT, 'Name      Years      Yearly Salary'

PRINT, '--------------------------------------------'

yearly_salary = FLTARR(4)

; One row at a time, total the monthly salaries.

FOR I = 0,3 DO BEGIN

; Use array subscripting notation to total twelve months of

; salary for each employee.

yearly_salary(I) = TOTAL(salary[*,I])

ENDFOR

; Create table structure, with each information column being an

; individual tag of the structure.

zz = BUILD_TABLE('name, years, yearly_salary')

; Print one row at a time.

FOR I = 0,3 DO BEGIN

; Print the employee information. Each column of information

; is now a tag of the zz table.

PRINT, Format="(A16, 3X, I5, 5X, F10.2)", zz(I).name, $
zz(I).years, zz(I).yearly_salary

ENDFOR

by_val = QUERY_TABLE(zz, '* Order By yearly_salary Desc')

; Print one row at a time.

FOR I = 0,3 DO BEGIN

; Print the employee information. Each column of information

; is a tag of the by_val table.

PRINT, Format="(A16, 3X, I5, 5X, F10.2)", by_val(I).name, $
by_val(I).years, by_val(I).yearly_salary

ENDFOR

by_val = QUERY_TABLE(zz, '* Order By name')

; Print one row at a time.

FOR I = 0,3 DO BEGIN

; Print the employee information.

PRINT, Format="(A16, 3X, I5, 5X, F10.2)", by_val(I).name, $
by_val(I).years, by_val(I).yearly_salary

ENDFOR

DIMENSION ALT(100), PRES(100), TEMP(100),

C	 VELO(100)

OPEN (UNIT=1, STATUS='NEW', FILE='aptv.dat')

.

. Other commands go here.

. 

WRITE (1,'(4(1x, G15.5))')

C	 (ALT(I), PRES(I), TEMP(I), VELO(I), I = 1,100)

END

; Open file for input.

OPENR, 1, 'aptv.dat'

; Define variable to hold 100 observations of data, 4 values per

; observation.

A = FLTARR(4,100)

; Read the data.

READF, 1, A

; Transpose array so that columns become rows.

A = TRANSPOSE(A)

; Extract altitude, pressure, temperature, and velocity data from

; variable A.

alt = A(*,0) & pres = A(*,1) &

temp = A(*,2) & velo = A(*,3)

; Close the file.

CLOSE, 1

; DC_READ_FIXED transfers values in “aptv.dat” to the variables

; alt, pres, temp, and velo. One value from each record is 

; transferred to each variable. DC_READ_FIXED creates the 

; variables as floating-point vectors, with a length that matches

; the number of values transferred into the variables. 

; DC_READ_FIXED handles the opening and closing of the file.

status = DC_READ_FIXED('aptv.dat', alt, $ 
pres, temp, velo, /Column, Format="%f")

; Create table structure, with each column of information being

; an individual tag of the table.

aptv = BUILD_TABLE('alt, pres, temp, velo')

DIMENSION ALT(100), PRES(100), TEMP(100), 

C	 VELO(100)

OPEN (UNIT=1, STATUS='NEW', FILE='aptv.dat')

.

.			 Other commands go here.

.

WRITE (1,'(4(1x,G15.5))') ALT, PRES, TEMP, 

C	 VELO

END

; Create a floating-point array to hold the data.

alt = FLTARR(100)

; Create more floating-point arrays, all the same size as alt.

pres = alt & temp = alt & velo = alt

; Open file for input.

OPENR, 1, 'aptv.dat'

; Read the data.

READF, 1, alt, pres, temp, velo

; Close the file.

CLOSE, 1

; Create a floating-point array to hold the data.

alt = FLTARR(100)

; Create more floating-point arrays, all the same size as alt.

pres = alt & temp = alt & velo = alt

; DC_READ_FIXED handles the opening and closing of the file. It 

; reads values from aptv.dat and stores them in the variables 

; alt, pres, temp, and velo. By default, the data is read as row-

; oriented data. The returned value status can be checked to see 

; if the process completed successfully.

status = DC_READ_FIXED('aptv.dat', alt, $
pres, temp, velo, Format="%f")

DIMENSION ALT(100), PRES(100), TEMP(100), 

C	 VELO(100)

CHARACTER*10 OBS(100)

OPEN (UNIT = 1, STATUS = 'NEW', FILE = 

C	 'aptvo.dat')

.

. Other commands go here.

.

WRITE (1,'(4(1X,G15.5), 2X, A)') (ALT(I), 

C	 PRES(I), TEMP(I), VELO(I), OBS(I), I = 1,100)

END

; Access file. This example reads files containing from 0 to 100

; records.

OPENR, 1, 'aptvo.dat'

; Create a floating-point array to hold the data.

alt = FLTARR(100)

; Create more floating-point arrays, all the same size as alt.

pres = alt & temp = alt & velo = alt

; Define string array.

obs = STRARR(100)

; Define scalar string.

obss = ' '

; Initialize counter.

I = 0

; Beginning of read loop.

WHILE NOT EOF(1) DO BEGIN

; Read scalars; the last one is a string variable, and by

; default, the first four are floating-point variables.

READF, 1, alts, press, temps, velos, obss, $
Format="(4(1X, G15.5), 2X, A10)"

alt(I) = alts & pres(I) = press

temp(I) = temps & velo(I) = velos

; Store in each vector.

obs(I) = obss

; Increment counter and check for too many records.

IF I LE 99 THEN I = I+1 ELSE CLOSE,1 & $ 
STOP, "Too many records."

ENDWHILE

; Close the file.

CLOSE, 1

alt = alt(0:I-1)

; Define string array; let other variables use default 

; floating-point data type.

obs = STRARR(100) 

; DC_READ_FREE handles the opening and closing of the file. It

; reads values from aptvo.dat and stores them in the variables 

; alt, pres, temp, velo, and obs. The data is being read as column 

; oriented data.

; Because Resize was included with the function call, all five

; variables are resizable and redimensioned to match the number

; of values actually transferred from the file. The returned

; value status can be checked to see if the process completed

; successfully.

status = DC_READ_FIXED('aptvo.dat', alt, pres, temp, velo, $
obs, /Column, Format="(4(1X, G15.5), 2X, A10)", $ 
Resize=[1, 2, 3, 4, 5])

abc = STRING([65B,66B,67B])

abc = STRING([byte('A'),byte('B'),byte('C')])

abc = STRING('A'+'B'+'C')

; Create a string array named A. 

A = STRING(Format='("The values are:", ' + $
', (I))', INDGEN(5))

; Display information about A.

INFO, A

; Print the result.

FOR I = 0, 5 DO PRINT, A(I)

A STRING = Array(6)

The values are:
0
1
2
3
4