ID: Q151262
The information in this article applies to:
Sequential access files, plain text files, are the types of files that you will encounter the most in Visual Basic for Applications. In a sequential access file, each character in the file is assumed to represent either a text character or a text formatting sequence, such as a tab or a newline character. Files such as CSV (Comma-Separated Value), TXT (Tab Delimited) and PRN (Space Formatted) are examples of sequential access files.
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The advantages of binary access files are as follows:
When you open a file for sequential access, you open it to perform one of the following operations:
Open filename For [Input | Output | Append] As filenumber Len=buffersize
When you use sequential access to open a file for Input, the file must
already exist; otherwise, Visual Basic for Applications generates a
trappable error. When you try to open a nonexistent file for Output or for
Append, the Open statement actually creates the file first, and then opens
it. Each time you open the file, you must use the Close statement to close
the file before reopening the file for another type of operation.
To retrieve the contents of a text file, first open the file for sequential
Input. Then, use Line Input # or Input # to copy the file into variables. Use Line Input # when you need to read a file, one line at a time. With delimited files (such as CSV), use Input # to read each line of the file into a list of variables.
Use Line Input # with a file opened for sequential access if the data is stored in the file one line at a time. The Line Input # statement reads from a file one character at a time until it encounters a carriage return (Chr(13)) or a carriage return-linefeed sequence. Carriage return-linefeed sequences are skipped rather than appended to the character string.
The following sample code uses the Line Input # statement to read data in from a sample text file called Textfile.txt, one line at a time.
NOTE: You will have to create the text file called Textfile.txt, if one does not already exist.
Sub ReadStraightTextFile()
Dim LineofText As String
' Open the file for Input.
Open "TEXTFILE.TXT" For Input As #1
' Read each line of the text file into a single string
' variable.
Do While Not EOF(1)
Line Input #1, LineofText
MsgBox LineofText
Loop
' Close the file.
Close #1
End Sub
As mentioned before, use Input # to read delimited files. When read, standard string or numeric data is assigned to variables as they appear in the text file. Delimiting commas or blank lines within the file are returned as Empty. Double quotation marks ("") that surrounds each field in
the input data is ignored and fields surround with #s (pound signs) can be interpreted as dates. When using Input #, data items in a file must appear in the same order as the variables in the variable list and be matched with
variables of the same data type. If the actual data doesn't match the variable type, you may encounter run-time errors.
If you have a text file named Delimit.txt and enter the following data, the
macro below will read in the data, one line at a time.
"Smith", "John", 22, "123 Main St.", "New York", "NY", 32432
"Doe", "Jane", 33, "324 Elm Ln.", "San Diego", "CA", 23542
"Adams", "Bill", 45, "4523 Oak Cir.", "Miami", "FL", 52343
"Jones", "Tom", 23, "2335 Maple Dr.", "Houston", "TX", 23453
The following sample code uses the Input # statement to read data from the
sample text file into variables:
Sub ReadDelimitedTextFile()
Dim LName As String, FName As String, Addr As String, City As String
Dim state As String
Dim age As Integer
' Open the file for Input.
Open "DELIMIT.TXT" For Input As #1
' Read each line of the text file into the list of variables
' until the end of the file is reached.
Do While Not (EOF(1))
Input #1, LName, FName, age, Addr, City, state, zip
MsgBox LName & ", " & FName & ", " & age & ", " & Addr & ", " _
& City & ", " & state & ", " & zip
Loop
' Close the file.
Close 1
End Sub
To store the contents of variables in a sequential text file, open it for sequential access, and then use either the Print # or Write # statement to write the data to the file.
The Write # statement is used to write raw data to the text file as comma- delimited and has the following syntax:
Write #filenumber[,outputlist]
When you write to the file using Write #, string fields are surrounded
with
double quotation marks and date fields are surrounded with #s (pound signs). In this respect, the Write # is a companion to Input #. The following macro demonstrates how you can write to a delimited text file:
Sub WriteFile()
Dim LName As String
Dim BDay As Date
Dim age As Integer
' Create a new text file called Test.txt.
Open "TEST.TXT" For Output As #1
' Create and then write the first "record."
LName = "Doe"
BDay = #1/1/95#
age = 1
Write #1, LName, BDay, age
' Create and then write the second "record."
LName = "Smith"
BDay = #4/29/56#
age = 39
Write #1, LName, BDay, age
' Create and then write the third "record."
LName = "Jones"
BDay = #5/1/80#
age = 15
Write #1, LName, BDay, age
' Close the file.
Close #1
End Sub
After the WriteFile macro is finished, you will have a comma-delimited
text
file named Test.txt that looks as follows:
"Doe",#1995-01-01#, 1
"Smith",#1956-04-29#,39
"Jones",#1980-05-01#,15
Unlike Write #, the Print # statement writes display-formatted data (or
space-formatted data) to a sequential file. The Print # statement has the
following syntax:
Print #filenumber,[outputlist]
In the output variable list for Print #, you can specify a number of
spaces
to separate fields. For more information, search for "Print # Statement," using the Microsoft Excel Help Index.
If you change Write # to Print # in the previous WriteFile macro, the Test.txt file would look something like this instead:
Doe 1/1/95 1
Smith 4/29/56 39
Jones 5/2/80 15
Note that when you Open a file for Output, if the file already exists, you are essentially replacing the contents of the file when you write to it. The new data that is written is not appended to the file. In order to append data to the end of a file, you must Open the file for Append. All data that is written to a file opened for Append is added to the end of the
file. You cannot modify the "records" in a file that is opened for sequential access. What you have to do is as follows:
1. Open the file for Input and read all of the data into variables.
2. Close the file.
3. Make the necessary modifications to the data contained in the variables.
4. Open the file for Output and write all of the modified data to the
file.
5. Close the file.
Because of all the steps required to make modifications to a file opened for sequential access, sequential access may not be the most efficient method for modifying data in a text file, especially if the text file is large.
Additional query words: 5.00 5.00a 5.00c 7.00 8.00
Keywords : kbprg kbdta kbdtacode PgmHowto KbVBA
Version : WINDOWS:5.0,5.0c,7.0,97; MACINTOSH:5.0,5.0a,98
Platform : MACINTOSH WINDOWS
Issue type : kbhowto
Last Reviewed: May 18, 1999