Reading all files in Folder and showing content in Excel - vba

Question

I want to show 7000 files content that are in a folder and in excel?
I have a found a piece of code that helped me but its only reading one by one. However, I want to read 7000 all in one go. Please help.
Option Explicit
Sub Import_TXT_File()
Dim strg As Variant
Dim EntireLine As String
Dim FName As String
Dim i As String
Application.ScreenUpdating = False
FName = Application.GetOpenFilename("Text Files (*.txt), *.txt", , "Choose File to Import")
Open FName For Input Access Read As #1
i = 1
While Not EOF(1)
Line Input #1, EntireLine
strg = EntireLine
'Change "Sheet1" to relevant Sheet Name
'Change "A" to the relevant Column Name
Sheets("Sheet1").Range("A" & i).Value = strg
i = i + 1
Wend
EndMacro:
On Error GoTo 0
Application.ScreenUpdating = True
Close #1
End Sub

Answer 1

user1185158
The code which you are using will be very slow when you are reading 7000 files. Also there is no code which can read 7000 files in 1 go. You will have to loop through the 7000 files. However there is one good news :) Instead of looping through every line in the text file, you can read the entire file into an array and then write it to excel. For example see this code which is very fast as compared to the code that you have above.
TRIED AND TESTED
Sub Sample()
Dim MyData As String, strData() As String
Open "C:\MyFile.Txt" For Binary As #1
MyData = Space$(LOF(1))
Get #1, , MyData
Close #1
strData() = Split(MyData, vbCrLf)
End Sub
Now using the same code in a loop we can write it into an Excel File
'~~> Change this to the relevant path
Const strPath As String = "C:\Temp\"
Sub Sample()
Dim ws As Worksheet
Dim MyData As String, strData() As String
Dim WriteToRow As Long, i As Long
Dim strCurrentTxtFile As String
Set ws = Sheets("Sheet1")
'~~> Start from Row 1
WriteToRow = 1
strCurrentTxtFile = Dir(strPath & "*.Txt")
'~~> Looping through all text files in a folder
Do While strCurrentTxtFile <> ""
'~~> Open the file in 1 go to read it into an array
Open strPath & strCurrentTxtFile For Binary As #1
MyData = Space$(LOF(1))
Get #1, , MyData
Close #1
strData() = Split(MyData, vbCrLf)
'~~> Read from the array and write to Excel
For i = LBound(strData) To UBound(strData)
ws.Range("A" & WriteToRow).Value = strData(i)
WriteToRow = WriteToRow + 1
Next i
strCurrentTxtFile = Dir
Loop
MsgBox "Done"
End Sub
What the above code does is that it reads the contents of the 7000 text files in sheet 1 (one below the other). Also I have not included error handling. Please do that.
CAUTION: If you are reading heavy text files, say, each file has 10000 lines then you will have to tweak the code in the above scenario as you will get errors. for example
7000 Files * 10000 lines = 70000000 lines
Excel 2003 has 65536 rows and Excel 2007/2010 has 1048576 rows.
So once the WriteRow reaches the maximum row, you might want to read the text file contents into Sheet 2 and so on...
HTH
Sid

Answer 2

Taking Siddharth's solution a little further. You probably don't want to write each row one at a time, calls to the worksheet are extremely slow in Excel, it is better to do any looping in memory and write back in one fell swoop :)
Sub Sample()
Dim ws As Worksheet
Dim MyData As String, strData() As String, strData2() As String
Dim WriteToRow As Long, i As Long
Dim strCurrentTxtFile As String
Set ws = Sheets("Sheet1")
'~~> Start from Row 1
WriteToRow = 1
strCurrentTxtFile = Dir(strPath & "*.Txt")
'~~> Looping through all text files in a folder
Do While strCurrentTxtFile <> ""
'~~> Open the file in 1 go to read it into an array
Open strPath & strCurrentTxtFile For Binary As #1
MyData = Space$(LOF(1))
Get #1, , MyData
Close #1
strData = Split(MyData, vbCrLf)
'Resize and transpose 1d array to 2d
ReDim strData2(1 To UBound(strData) + 1, 1 To 1)
For i = 1 To UBound(strData)
strData2(i, 1) = strData(i - 1)
Next i
Sheet1.Range("A1").Offset(Sheet1.Rows.Count - 1, 0).End(xlUp).Offset(1).Resize(UBound(strData), 1).Value = strData2
strCurrentTxtFile = Dir
Loop
MsgBox "Done"
End Sub