Question: I'm trying to check a TSV of results and want to see how many times F and S come up (for failure or success) however I'm not sure how to doing this counting, or how to having it search the file

I've come across something that is sort of what I'm looking for: [Python Program how to count number of times the letter c shows up](https://stackoverflow.com/questions/13103148/python-program-how-to-count-number-of-times-the-letter-c-shows-up)

```
def countletter(S, F): 
    count = 0
    for x in S:
        if x.lower() == F.lower():
            count += 1
    return count

print (countletter("abcdefFf","F"))

```

But it isn't perfect and I'm not sure how to make it search the file.

Answer: 
**Before trying this solution be sure that you read the "Things I've done" paragraph from the question (and tried what applies to you)**

The Exception was thrown upon opening the Document; on the machine which generated the Excels, the files were generated invalid.

The solution was to change the Format of the numbers.

Go into System Configuration -> Time, Language and Region -> Language

![Go into Systemconfiguration -> Time, Language and Region -> Language](https://i.stack.imgur.com/fLoOO.png)

Tap on the highlighted Hyperlink

Open Advanced Settings

![Open Advanced Settings](https://i.stack.imgur.com/ynFuX.png)

Change the delimiter to a point "."
![Change the delimiter to a point "."](https://i.stack.imgur.com/Pzp8j.png)
We have converted our Client / Server solution from 4GL language to C#, where embedded C# code below worked without any issue before, and started to receive same error message.

```
Excel.Application excelApp = new Excel.Application();
Excel.Workbook excelWorkbook = excelApp.Workbooks.Open(fileExcel,
    0, false, 5, "", "", false, Excel.XlPlatform.xlWindows, "",
    true, false, 0, true, false, false);

```

I have followed all the instructions in this thread, but to no avail, until I have realised that in our case at least fileExcel, which contains the full path with the name of the file and defined as `System.String fileExcel` had trailing spaces, e.g. instead of "C:\temp\MyTest.xls" it was "C:\temp\MyTest.xls[many many spaces]". 
Once I have added `Trim()` to fileExcel as below, all went back to normal. Hope it will help to someone in the future.

```
Excel.Workbook excelWorkbook = excelApp.Workbooks.Open(fileExcel.Trim(),
    0, false, 5, "", "", false, Excel.XlPlatform.xlWindows, "",
    true, false, 0, true, false, false);

```