I know this is an old question, but the problem is not going away soon. CSV files are easy to generate from most programming languages, rather small, human-readable in a crunch with a plain text editor, and ubiquitous.
The problem is not only with dates in text fields, but anything numeric also gets converted from text to numbers. A couple of examples where this is problematic:
- ZIP/postal codes
- telephone numbers
- government ID numbers
which sometimes can start with one or more zeroes (0), which get thrown away when converted to numeric. Or the value contains characters that can be confused with mathematical operators (as in dates: /, -).
Two cases that I can think of that the "prepending =" solution, as mentioned previously, might not be ideal is
- where the file might be imported into a program other than MS Excel (MS Word's Mail Merge function comes to mind),
- where human-readability might be important.
My hack to work around this
If one pre/appends a non-numeric and/or non-date character in the value, the value will be recognized as text and not converted. A non-printing character would be good as it will not alter the displayed value. However, the plain old space character (\s, ASCII 32) doesn't work for this as it gets chopped off by Excel and then the value still gets converted. But there are various other printing and non-printing space characters that will work well. The easiest however is to append (add after) the simple tab character (\t, ASCII 9).
Benefits of this approach:
- Available from keyboard or with an easy-to-remember ASCII code (9),
- It doesn't bother the importation,
- Normally does not bother Mail Merge results (depending on the template layout - but normally it just adds a wide space at the end of a line). (If this is however a problem, look at other characters e.g. the zero-width space (ZWSP, Unicode U+200B)
- is not a big hindrance when viewing the CSV in Notepad (etc),
- and could be removed by find/replace in Excel (or Notepad etc).
- You don't need to import the CSV, but can simply double-click to open the CSV in Excel.
If there's a reason you don't want to use the tab, look in an Unicode table for something else suitable.
Another option
might be to generate XML files, for which a certain format also is accepted for import by newer MS Excel versions, and which allows a lot more options similar to .XLS format, but I don't have experience with this.
So there are various options. Depending on your requirements/application, one might be better than another.
Addition
It needs to be said that newer versions (2013+) of MS Excel don't open the CSV in spreadsheet format any more - one more speedbump in one's workflow making Excel less useful... At least, instructions exist for getting around it. See e.g. this Stackoverflow: How to correctly display .csv files within Excel 2013?
.
1234
is an integer and@2000-04-25@
is a date, but"1234"
and"april25"
are unambiguously text strings. – Crosshead