LING 408/508: Programming for Linguists Lecture 27 December 9 th Class Inheritance Higher order functions map(function,list) apply function to each member of the list in turn creating a transformed list Higher order functions map(function,list) apply function to each member of the list in turn creating a transformed list inline anonymous function: lambda example: x.x+x lambda x:x+x Higher order functions reduce(function,list) apply 2-argument function from left to right 1 st argument will be cumulative value 2 nd argument is fresh argument from the list number of cannonballs in pyramid (Wikipedia): Higher order functions filter(function,list) apply function to each member of the list collect those for which the function returns true Standard Deviation Example textbook code seems problematic Median Median: average of middle two if even number of elements middle element of list if odd number of elements Lists Comparisons: default sort order: cmp(x,y) returns -1 (x y) Lists create a list of Student objects in variable data Dictionaries Hash table: List: delimiter: square brackets Dictionary: delimiter: curly braces Dictionaries Word frequency table program: tokenization Dictionaries Word frequency table program default = 0 Dictionaries Word frequency table program Corpus Lead NYTimes article one year ago tomorrow: Non-ASCII Corpus wc.py for non- ascii regular expression convert and insert space for curly quotes, commas, single quotes, and periods not preceded by a capital letter sys.argv list holds command line filename and n most freq words Results sys.argv[1] sys.argv[2] top 2 content words in the article Adminstrivia TCEs are fully online (paper TCEs are history) https://tce.oirps.arizona.edu/TCEOnline