INPUT (file statement): Difference between revisions

From QB64 Phoenix Edition Wiki
Jump to navigation Jump to search
m (Removed protection from "INPUT (file statement)")
No edit summary
 
(3 intermediate revisions by the same user not shown)
Line 2: Line 2:




{{PageSyntax}}  
{{PageSyntax}}
: [[INPUT #]]{{Parameter|fileNumber&}}, {{Parameter|variable1}}[, {{Parameter|variable2}}, ..., {{Parameter|variableN}}]
: [[INPUT #]]{{Parameter|fileNumber&}}, {{Parameter|variable1}}[, {{Parameter|variable2}}, ..., {{Parameter|variableN}}]




{{Parameters}}
{{PageParameters}}
* {{Parameter|fileNumber&}} is a positive [[LONG]] integer value used to [[OPEN]] the file FOR [[INPUT (file mode)|INPUT]] mode.  
* {{Parameter|fileNumber&}} is a positive [[LONG]] integer value used to [[OPEN]] the file FOR [[INPUT (file mode)|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.
* The [[Variable Types|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).
* 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).


Line 14: Line 14:
{{PageDescription}}
{{PageDescription}}
* The file number can be determined by the programmer or be an unused number returned by the [[FREEFILE]] function.
* 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 [[type]]s being read. [[STRING]] variables can return unquoted numeric values.
* Variable types must match the numerical [[Variable Types|type]]s being read. [[STRING]] variables can return unquoted numeric values.
* Leading or trailing spaces of [[STRING]] values must be inside of quotes. [[WRITE (file statement)|WRITE #]] writes strings inside of quotes automatically. [[PRINT (file statement)|PRINT #]] removes quotes.
* Leading or trailing spaces of [[STRING]] values must be inside of quotes. [[WRITE (file statement)|WRITE #]] writes strings inside of quotes automatically. [[PRINT (file statement)|PRINT #]] removes quotes.
* [[INPUT #]] will read each value until it encounters a comma for the next value in a list.
* [[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.
* Use the [[EOF]] function to avoid reading past the end of a file.
* Files created by [[WRITE (file statement)|WRITE #]] usually have the same number of values on each file line. If INPUT reads more or less values, it may read beyond the [[EOF|end of file]] or return bad data.
* Files created by [[WRITE (file statement)|WRITE #]] usually have the same number of values on each file line. If INPUT reads more or less values, it may read beyond the [[EOF|end of file]] or return bad data.
* Use the [[LINE INPUT (file statement)]] for files created with PRINT # or PRINT #, USING.  
* 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.'''
* '''INPUT can read Excel CSV files, but beware of unquoted text or numerical values containing commas.'''


Line 25: Line 25:
{{PageExamples}}
{{PageExamples}}
''Example 1:'' Writes new data to a text file sequentially and reads it back to the program screen.
''Example 1:'' Writes new data to a text file sequentially and reads it back to the program screen.
{{CodeStart}} '' ''
{{CodeStart}}
filename$ = "testfile.dat"  
filename$ = "testfile.dat"
x = 1: y = 2: z$ = "Three"  
x = 1: y = 2: z$ = "Three"


{{Cl|OPEN}} filename$ {{Cl|FOR...NEXT|FOR}} {{Cl|OUTPUT}} {{Cl|AS}} #1 'opens and clears an existing file or creates new empty file  
{{Cl|OPEN}} filename$ {{Cl|FOR...NEXT|FOR}} {{Cl|OUTPUT}} {{Cl|AS}} #1 'opens and clears an existing file or creates new empty file
{{Cl|WRITE (file statement)|WRITE}} #1, x, y, z$  
{{Cl|WRITE (file statement)|WRITE}} #1, x, y, z$
{{Cl|CLOSE}} #1  
{{Cl|CLOSE}} #1


{{Cl|PRINT}} "File created with data. Press a key!"  
{{Cl|PRINT}} "File created with data. Press a key!"
K$ = {{Cl|INPUT$}}(1) 'press a key  
K$ = {{Cl|INPUT$}}(1) 'press a key


{{Cl|OPEN}} filename$ {{Cl|FOR (file statement)|FOR}} {{Cl|INPUT (file mode)|INPUT}} {{Cl|AS}} #2 'opens a file to read it  
{{Cl|OPEN}} filename$ {{Cl|FOR (file statement)|FOR}} {{Cl|INPUT (file mode)|INPUT}} {{Cl|AS}} #2 'opens a file to read it
{{Cl|INPUT (file statement)|INPUT}} #2, a, b, c$  
{{Cl|INPUT (file statement)|INPUT}} #2, a, b, c$
{{Cl|CLOSE}} #2  
{{Cl|CLOSE}} #2


{{Cl|PRINT}} a, b, c$  
{{Cl|PRINT}} a, b, c$
{{Cl|WRITE}} a, b, c$
{{Cl|WRITE}} a, b, c$


{{Cl|END}} '' ''
{{Cl|END}}
{{CodeEnd}}
{{CodeEnd}}
{{OutputStart}} 1          2          Three
{{OutputStart}} 1          2          Three
Line 56: Line 56:


''Example 2:'' Commas inside of string values will not affect the INPUT value as those commas are not [[WRITE (file statement)|WRITE]] separators.
''Example 2:'' Commas inside of string values will not affect the INPUT value as those commas are not [[WRITE (file statement)|WRITE]] separators.
{{CodeStart}} '' ''
{{CodeStart}}
x$ = "Hello, how are you?"
x$ = "Hello, how are you?"
y$ = "I'm fine."
y$ = "I'm fine."
Line 70: Line 70:
{{Cl|CLOSE}} #1
{{Cl|CLOSE}} #1


{{Cl|PRINT}} a$, b$  
{{Cl|PRINT}} a$, b$
{{Cl|WRITE}} a$, b$ '' ''
{{Cl|WRITE}} a$, b$
{{CodeEnd}}
{{CodeEnd}}
{{OutputStart}}Hello, how are you?        I'm fine.  
{{OutputStart}}Hello, how are you?        I'm fine.
"Hello, how are you?","I'm fine."{{OutputEnd}}
"Hello, how are you?","I'm fine."{{OutputEnd}}
{{TextStart}}"Hello, how are you?","I'm fine."{{TextEnd}}
{{TextStart}}"Hello, how are you?","I'm fine."{{TextEnd}}
Line 80: Line 80:


{{PageSeeAlso}}
{{PageSeeAlso}}
* [[INPUT (file mode)]], [[LINE INPUT (file statement)|LINE INPUT #]], [[INPUT$]] {{text|(file input)}}
* [[INPUT (file mode)]], [[LINE INPUT (file statement)|LINE INPUT #]], [[INPUT$]] {{Text|(file input)}}
* [[INPUT]], [[LINE INPUT]], [[INPUT$]] {{text|(keyboard input)}}
* [[INPUT]], [[LINE INPUT]], [[INPUT$]] {{Text|(keyboard input)}}
* [[PRINT (file statement)|PRINT #]], [[PRINT USING (file statement)|PRINT #, USING]]  
* [[PRINT (file statement)|PRINT #]], [[PRINT USING (file statement)|PRINT #, USING]]
* [[GET|GET #]]
* [[GET|GET #]]




{{PageNavigation}}
{{PageNavigation}}

Latest revision as of 20:25, 26 January 2024

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]


Parameters

  • 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"
Screen output: PRINT string values will not display enclosing quotes. WRITE screen displays will.
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


Navigation:
Main Page with Articles and Tutorials
Keyword Reference - Alphabetical
Keyword Reference - By usage
Retrieved from "https://qb64phoenix.com/qb64wiki/index.php?title=INPUT_(file_statement)&oldid=8708"