I created a datafile as follows: ESTgrowth = FileNameJoin[{"Filepath", "ESTgrowth"}]; open = OpenAppend[ESTgrowth]; Write[open, newdata]; (*"newdata" is a list of data appended to "ESTgrowth" *) Close[open]; This `code` appends data stream as follows: {-17.071, 137.567, 16.554, 0.65} {-16.873, 136.138, 16.934, 0.7} {-15.397, 135.738, 16.894, 0.7} {-14.7, 135.982, 15.9, 0.6} Then I tried to import the data file to present it using `TableForm[...]`. Of course, Import[ESTgrowth, "Table"] would NOT work because the data stream consists of lists of data only. My question is how to automatically put the data stream into the following format: { {-17.071, 137.567, 16.554, 0.65}, {-16.873, 136.138, 16.934, 0.7}, {-15.397, 135.738, 16.894, 0.7}, {-14.7, 135.982, 15.9, 0.6} } for `TableForm[...]` to work as expected. Screenshot of my dataset with Extra commas placed in fixed positions in each row. [![enter image description here][1]][1] Screenshot of NOT working code. [![enter image description here][2]][2] [1]: https://i.sstatic.net/kB1sA.png [2]: https://i.sstatic.net/d3j56.png