Using regular expressions
For research, you may need to download data from open-access websites or authentication-required databases. These data sources provide data in various formats, and most of the data supplied are very likely well-organized. For example, many economic and financial databases provide data in the CSV format, which is a widely supported text format to represent tabular data. A typical CSV format looks like this:
id,name,score 1,A,20 2,B,30 3,C,25
In R, it is convenient to call
read.csv() to import a CSV file as a data frame with the right header and data types because the format is a natural representation of a data frame.
However, not all data files are well organized, and dealing with poorly organized data is painstaking. Built-in ...