Macroeconmics. □ Economics at the world scale. □ Current Account Balance is
like income – balance of trade, foreign aid, interest and dividends on foreign.
Announcements ! !
No lecture Wds, also no section. I will be in Lab hours Wds, and we will do some work on dictionaries and file writing.
ECS 10 11/19
Makeup Assignment !
Files, dictionaries, file writing, sorting.
Macroeconmics Economics at the world scale. Current Account Balance is like income – balance of trade, foreign aid, interest and dividends on foreign investment. ! Does not include domestic production or consumption; just income with respect to the rest of the world. ! US’s CAB a big negative number, China’s CAB a big positive number. ! !
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Current Account Balance
Data source
Data source
Maybe we should not freak out. USA is a big economy; the fact that it has the biggest anything in the world might not be a disaster. ! We buy a lot of stuff; mostly stuff from China and oil. ! if we weren’t going into debt, it would not be a problem at all. ! Are we buying more stuff at a higher rate than other countries? ! Compare CAB and GDP (size of economy). !
Combine two data files Get CAB and GDP lists from CIA. Combine by country. ! Use a dictionary where country is the key. ! Read one file, say GDP, build dictionary. ! Read CAB file, look up country, get GDP, and compute R. ! Save [R, country name] in a list of lists. ! Very common data wrangling task.
Goal Compute R = CAB/GDP for each country Produce a list of countries, sorted by R ! Write out file readable in Excel, ManyEyes… ! Where does USA show up in this list? China? ! !
Skills: combining data ! Sorting ! 3 loops !
Sorting
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Sorting is putting a list into order – A,B,C… or 1,2,3… ! Python has a sort method for lists.
Sorting list of lists?
Data file formats
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Sorts by FIRST ITEM in each list. So if we want to sort by R, R better be the first item in each list.
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Excel, ManyEyes, other programs read text files containing data. ! Issues with multi-part names, etc, make it hard to use plain text files. ! .csv – commas separate data items ! .tsv – tabs separate data items ! This CIA data is tab-separated ! We’d like to produce tab-separated output file !
Let’s sort something real… ! !
State population file, but tab-separated Sort by population
Output file
Make list of lists
