INPUT (file statement)
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The INPUT # file or port statement reads sequential data using one variable or a comma separated list of matching variable types.
Syntax
- INPUT #fileNumber&, variable1[, variable2, ..., variableN]
- fileNumber& is a positive LONG integer value used to OPEN the file FOR INPUT mode.
- The type of the variable used defines the value or list of values to be returned from the file. Numeric types must match the values returned.
- As reflected in the syntax you can list a number of variables with different types seperated by a comma and they will hold the values in the file (keep in mind that the information in the file should match the variable types used).
Description
- The file number can be determined by the programmer or be an unused number returned by the FREEFILE function.
- Variable types must match the numerical types being read. STRING variables can return unquoted numeric values.
- Leading or trailing spaces of STRING values must be inside of quotes. WRITE # writes strings inside of quotes automatically. PRINT # removes quotes.
- INPUT # will read each value until it encounters a comma for the next value in a list.
- Use the EOF function to avoid reading past the end of a file.
- Files created by WRITE # usually have the same number of values on each file line. If INPUT reads more or less values, it may read beyond the end of file or return bad data.
- Use the LINE INPUT (file statement) for files created with PRINT # or PRINT #, USING.
- INPUT can read Excel CSV files, but beware of unquoted text or numerical values containing commas.
Examples
Example 1: Writes new data to a text file sequentially and reads it back to the program screen.
filename$ = "testfile.dat" x = 1: y = 2: z$ = "Three" OPEN filename$ FOR OUTPUT AS #1 'opens and clears an existing file or creates new empty file WRITE #1, x, y, z$ CLOSE #1 PRINT "File created with data. Press a key!" K$ = INPUT$(1) 'press a key OPEN filename$ FOR INPUT AS #2 'opens a file to read it INPUT #2, a, b, c$ CLOSE #2 PRINT a, b, c$ WRITE a, b, c$ END |
1 2 Three 1,2,"Three" |
1,2,"Three" |
- File content: WRITE string values will include quotation marks, but they are not required to read the file value as a string.
Example 2: Commas inside of string values will not affect the INPUT value as those commas are not WRITE separators.
x$ = "Hello, how are you?" y$ = "I'm fine." OPEN "testinp.dat" FOR OUTPUT AS #1 WRITE #1, x$, y$ CLOSE #1 OPEN "testinp.dat" FOR INPUT AS #1 INPUT #1, a$, b$ CLOSE #1 PRINT a$, b$ WRITE a$, b$ |
Hello, how are you? I'm fine. "Hello, how are you?","I'm fine." |
"Hello, how are you?","I'm fine." |
- File content: Commas inside of strings delimited with quotes will be ignored. WRITE will always enclose string values in quotes.
See also
- INPUT (file mode), LINE INPUT #, INPUT$ (file input)
- INPUT, LINE INPUT, INPUT$ (keyboard input)
- PRINT #, PRINT #, USING
- GET #