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Useful Pandas Snippets

A personal diary of DataFrame munging over the years.

Convert Series datatype to numeric (will error if column has non-numeric values)
(h/t @makmanalp)

A "Best of the Best Practices" (BOBP) guide to developing in Python.

	#List unique values in a DataFrame column
	pd.unique(df.column_name.ravel())

	#Convert Series datatype to numeric, getting rid of any non-numeric values
	df['col'] = df['col'].astype(str).convert_objects(convert_numeric=True)

	#Grab DataFrame rows where column has certain values
	valuelist = ['value1', 'value2', 'value3']
	df = df[df.column.isin(value_list)]

	obesity = read.csv(
	'http://www.stat.berkeley.edu/classes/s133/data/obesity.csv',
	stringsAsFactors = F
	)
	names(obesity) = gsub("\\.", "_", names(obesity))
	# add column with two letter state names and
	obesity = plyr::mutate(obesity,
	State = stringr::str_trim(State),
	state = state.abb[match(State, state.name)],
	)