At least 32 MB free memory. Actualy requirements depend on the size of your data files.
functional limitations:
Unregistered versions count the first 100 words in your source file only.
Zipfer description
Zipfer is a little tool by xTalk programmer Mark Schonewille. This software retrieves data from any text file, counts the words and creates a proper data file. From the resulting data file, Zipfer can calculate a number of statistics, such as a linear regression equation expressing the relationship between rank and frequency of each word. Additionally, Zipfer creates graphs, showing the zipf curve and errors estimated from the theoretical and actual frequencies. Zipfer also allows you to export the data for further exploration in more advanced tools such as Excel and SPSS. These files can also be opened by Zipfer again. It is also possible to export the graphs as JPEG pictures, for use in your papers and in websites.
Software Library
