Data Files
CFTool reads and writes simple text-based data files — columns of numbers separated by tabs or commas.
Each file consists of columns of numerical data separated by tabs or commas (other common separators are also recognised). By default, CFTool saves data in two, three, or four columns (the fourth when X errors are enabled):
| Column | Meaning |
|---|---|
| x-data | Independent variable |
| y-data | Dependent variable |
| σy (sigma y) | Uncertainty in y (optional) |
| σx (sigma x) | Uncertainty in x (optional) |
These files can be opened, edited, and re-saved directly within CFTool, or viewed in any spreadsheet or text editor.
01Opening data files
Use File ▸ Load Data to import a text file. When you open a file:
- The data are plotted immediately in the main figure window with temporary labels.
- If the file contains header rows (lines of text at the top), a dialog asks whether to use the top line as axis labels.
- If the file contains more than two numerical columns, a dialog prompts you to choose which columns represent x, y, and σy, σx.
Tip. CFTool automatically recognises tab- or comma-separated formats from most spreadsheets.
02File structure and saving
- Two-column files are assumed to be ordered x then y. (You can later swap axes with Edit ▸ Swap x and y if needed.) In this case CFTool saves immediately without additional prompts.
- Multi-column files require you to select which columns correspond to x, y, and σ the first time you open them.
- On the first save, CFTool warns before overwriting; subsequent saves proceed normally.
When you choose Save Data, the file is written as x y σ, columns separated by tabs.
Preserve your original. If you want to keep the original data file, always Save As under a new name before editing.
03Summary
| Action | Result |
|---|---|
| Open file | Data plotted in main window |
| File has text headers | Prompt to use top line as axis labels |
| File has >2 columns | Prompt to assign x, y, σ |
| Two-column file | Assumed x then y |
| Save | Overwrites original unless saved under a new name |
| Save As | Writes tab-separated x, y, σ columns |
