doug ybarbo alexland

scala, spark, akka dev designing & building distributed systems--data pipelines, machine learning systems, search

alexland / flatten.py

Last active December 24, 2015 17:29

flatten a nested sequence: distinguishes lists from strings, etc.

	# first, a compact one-liner but limited to 2D sequences (nested just one level):

	# obvious, but
	# "nested_list" refers to the nested list you want to flatten,
	# "row" refers to each list comprising the nested_list
	# "itm" refers to each element comprising each row


	def flatten(list2D):
	return [itm for row in list2d for itm in row]

alexland / exception_class_id.py

Created September 26, 2013 03:38

how to find the module an exception class was defined in


	try:
	...
	except Exception, e:
	print("caught an exception defined in class {0}".format(e.__class__.__module__))

alexland / commify.R

Created July 3, 2013 22:45

add commas to numbers comprising various R objects (eg, tables)

print_fn = function(x) {print(format(x, big.mark=','), quote=F)}

alexland / sort_tapply.R

Created October 10, 2012 02:13

sorting a data frame on a numeric variable conditioned on a factor variable


	DF1 = DF[order(DF$factor_var, -xtfrm(DF$numeric_var)),]
	DF1$idx = sequence(rle(as.character(DF1$factor_var))$lengths)


	$> # e.g., sort a data frame based on 'price' (numeric variable)
	$> # 'grouped by' the levels of 'color' (factor, or discrete variable)

	$> data(diamonds, package="ggplot2")

alexland / package-name-expander.R

Created October 8, 2012 06:02

for programatic update of an R package--avoid having to use complete filename with version appended


	pkg_name = paste("~/path/to/package", system('cd /path/to/package; ls adStats*', intern=T), sep="/")

	install.packages(pkg_name, repos=NULL, type="source")