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