Reading a DataFrame from a file

Reading a dataframe from delimiter separated data

You may want to read a DataFrame from a CSV (Comma separated values) file or maybe even from a TSV or WSV (tabs and whitespace separated files). If your file has the right extension, you can use the readtable function to read in the dataframe:

readtable("dataset.CSV")

But what if your file doesn’t have the right extension? You can specify the delimiter that your file uses (comma, tab, whitespace etc) as a keyword argument to the readtable function:

readtable("dataset.txt", separator=',')

Handling different comment comment marks

Data sets often contain comments that explain the data format or contain the license and usage terms. You usually want to ignore these lines when you read in the DataFrame.

The readtable function assumes that comment lines begin with the ’#’ character. However, your file may use comment marks like % or //. To make sure that readtable handles these correctly, you can specify the comment mark as a keyword argument:

readtable("dataset.csv", allowcomments=true, commentmark='%')