Programming Forums > Application Development > Visual Basic

cloud- · Apr 6th, 2005, 2:13 PM

how would i find out the number of lines in a textfile and
i also need to read a random line from the text file..
any ideas

thanks

chepfaust · Apr 6th, 2005, 2:40 PM

LOF(#x) will tell you the length of the textfile, where the x is the number you open the file as.

dunno about reading a random line though.

Rory · Apr 6th, 2005, 4:20 PM

Right, you can think about a line as being defined by a line break. Thus the number of lines in a string or text file is given by Ubound(Split(MyString,VbNewLine)) + 1.
Or more usefully, a random line is:

(Toggle Plain Text)

Dim MyLines() as String
Dim RandomLine as String
Randomize(Timer)
MyLines = Split(MyString,vbNewLine)
RandomLine = MyLines(Fix((Ubound(MyLines) + 1) * Rnd))

Hope this helps.

Infinite Recursion · Apr 6th, 2005, 11:16 PM

Rory, I declare you as being the resident VB wizard

cloud- · Apr 7th, 2005, 6:08 AM

hi thanks for the replys

but i dont understand how i can use what rory said

(Toggle Plain Text)

Function RndGetLine(Section As Integer) As String
Dim FsFile As String
FsFile = FreeFile
Open "C:\Cloud\test4.text" For Input As #FsFile
...??
..??
End Function

do i have to read the whole text file to a variable for your code to work
how do i do that?

(Toggle Plain Text)

Line Input #Fsfile, variable?

or does that read one line at a time?

thanks for the help

chepfaust · Apr 7th, 2005, 9:51 AM

Quote:

Originally Posted by cloud-

hi thanks for the replys

but i dont understand how i can use what rory said

do i have to read the whole text file to a variable for your code to work
how do i do that?

(Toggle Plain Text)

Line Input #Fsfile, variable?

or does that read one line at a time?

thanks for the help

better than line input; what rory did was use the split() function to chop up the entire text file and put each individual line into an array called "mylines."

MyLines = Split(MyString,vbNewLine)

then all you have to do is generate a random number up to the upper bound of the array and display the corresponding line of the array (which displays that line of the text file!). in this case the random line gets stored to the string "randomline."

RandomLine = MyLines(Fix((Ubound(MyLines) + 1) * Rnd))

cloud- · Apr 7th, 2005, 11:29 AM

But how do i get the textfile in that variable (MyString)?

thanks alot ^^

Rory · Apr 7th, 2005, 1:31 PM

Quote:

Originally Posted by Infinite Recursion

Rory, I declare you as being the resident VB wizard

Thanks! (I hope to learn a proper language some day)

(Toggle Plain Text)

Open "C:\AFile.txt" For Input As #1
    MyString = Input(LOF(1), 1)
Close #1

That will load a unicode file into the variable MyString. I do it in binary mode like this, but there are probably more elegant ways.

(Toggle Plain Text)

Dim MyString As String
Dim MyBuffer() As Byte
Open "C:\AFile.txt" For Binary Access Read As #1
    ReDim MyBuffer(LOF(1) - 1)
    Get 1, , MyBuffer
    MyString = StrConv(MyBuffer, vbUnicode)
    ReDim MyBuffer(0) 'Free up memory
Close #1

cloud- · Apr 7th, 2005, 2:43 PM

ahh tx ^^
but i get an error on :
RandomLine = MyLines(Fix((Ubound(MyLines) + 1) * Rnd))

saying expected array..
any ideas?

thanks alot

Rory · Apr 7th, 2005, 6:39 PM

Is there anything in Mylines?
The full code would be:

(Toggle Plain Text)

Dim MyLines() as String
Randomize(Timer)
Open "C:\AFile.txt" For Input As #1
MyLines = Split(Input(LOF(1), 1),vbNewLine)
Close #1
RandomLine = MyLines(Fix((Ubound(MyLines) + 1) * Rnd))

Apr 6th, 2005, 4:20 PM	#3
Rory Expert Programmer Join Date: Jan 2005 Location: London Posts: 542 Rep Power: 4	Right, you can think about a line as being defined by a line break. Thus the number of lines in a string or text file is given by Ubound(Split(MyString,VbNewLine)) + 1. Or more usefully, a random line is: (Toggle Plain Text) Dim MyLines() as String Dim RandomLine as String Randomize(Timer) MyLines = Split(MyString,vbNewLine) RandomLine = MyLines(Fix((Ubound(MyLines) + 1) * Rnd)) Dim MyLines() as String Dim RandomLine as String Randomize(Timer) MyLines = Split(MyString,vbNewLine) RandomLine = MyLines(Fix((Ubound(MyLines) + 1) * Rnd)) Hope this helps.

Apr 6th, 2005, 11:16 PM	#4
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,467 Rep Power: 8	Rory, I declare you as being the resident VB wizard __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Apr 7th, 2005, 6:08 AM	#5
cloud- Hobbyist Programmer Join Date: Jan 2005 Posts: 110 Rep Power: 4	hi thanks for the replys but i dont understand how i can use what rory said (Toggle Plain Text) Function RndGetLine(Section As Integer) As String Dim FsFile As String FsFile = FreeFile Open "C:\Cloud\test4.text" For Input As #FsFile ...?? ..?? End Function Function RndGetLine(Section As Integer) As String Dim FsFile As String FsFile = FreeFile Open "C:\Cloud\test4.text" For Input As #FsFile ...?? ..?? End Function do i have to read the whole text file to a variable for your code to work how do i do that? (Toggle Plain Text) Line Input #Fsfile, variable? Line Input #Fsfile, variable? or does that read one line at a time? thanks for the help

Apr 7th, 2005, 6:39 PM	#10
Rory Expert Programmer Join Date: Jan 2005 Location: London Posts: 542 Rep Power: 4	Is there anything in Mylines? The full code would be: (Toggle Plain Text) Dim MyLines() as String Randomize(Timer) Open "C:\AFile.txt" For Input As #1 MyLines = Split(Input(LOF(1), 1),vbNewLine) Close #1 RandomLine = MyLines(Fix((Ubound(MyLines) + 1) * Rnd)) Dim MyLines() as String Randomize(Timer) Open "C:\AFile.txt" For Input As #1 MyLines = Split(Input(LOF(1), 1),vbNewLine) Close #1 RandomLine = MyLines(Fix((Ubound(MyLines) + 1) * Rnd))

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Apr 6th, 2005, 2:13 PM	#1
cloud- Hobbyist Programmer Join Date: Jan 2005 Posts: 110 Rep Power: 4	reading a random line from a text file how would i find out the number of lines in a textfile and i also need to read a random line from the text file.. any ideas thanks

Apr 6th, 2005, 2:40 PM	#2
chepfaust Programmer Join Date: Feb 2005 Posts: 62 Rep Power: 4	LOF(#x) will tell you the length of the textfile, where the x is the number you open the file as. dunno about reading a random line though.

Apr 7th, 2005, 11:29 AM	#7
cloud- Hobbyist Programmer Join Date: Jan 2005 Posts: 110 Rep Power: 4	But how do i get the textfile in that variable (MyString)? thanks alot ^^

Apr 7th, 2005, 2:43 PM	#9
cloud- Hobbyist Programmer Join Date: Jan 2005 Posts: 110 Rep Power: 4	ahh tx ^^ but i get an error on : RandomLine = MyLines(Fix((Ubound(MyLines) + 1) * Rnd)) saying expected array.. any ideas? thanks alot

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Programming Forums > Application Development > Visual Basic

reading a random line from a text file