Class 17 — Friday March 12

Reading is fundamental

CVS Drugstore — Is not to be examined — CSV files yes

---

Look both ways

• Back or ahead

---

Agenda

• Dataset access and analysis

---

Downloads

• Program what_color_will_my_chrysanthemums_be.py

• Program csv_is_not_a_pharmacy.py

• Program what_day_is_it.py

---

To do list

• Review class artifacts

• Complete homeworks

• Prepare for Test 1 (03 / 17 / 2021)

---

Last class continued

• Introduced the Python relational operators: <, <=, >, >=, ==, and !=.

• Introduced the Python logical operators: and, or, not, in, and not in

• Determined whether its input pH level is acidic; i.e., less than 7.0

• Used relational operator < to help determine whether a soil pH sample was acidic.

Enter pH level: 6.5

True

Enter pH level: 7.0

False

Enter pH level: 7.5

False

• Program what_color_will_my_chrysanthemums_be.py uses an if statement to help determine the color of a chrysanthemum based on soil pH.

Enter soil pH level: 6.5

pink

Enter soil pH level: 7

blue

Enter soil pH level: 7.5

blue

---

Program csv_is_not_a_pharmacy.py — streamlining getting a dataset

• Some datasets for analyzing

• elevations.csv

Location, Author, Max Height, Min Height

Narnia, Lewis, 4810, -10

Neverland, Milne, 426, -2

Oz, Baum, 1231, 679

Sleepy Hollow, Irving, 1629, 304

Stars Hollow, Sherman-Palladino, 725, 152

Toyland, MacDonough, 6187, 0

Wonderland, Carroll, 5895, -5

• oceania.csv

Country, Females, Males

Australia, 11175724, 11092660

Fiji, 421365, 439258

French Polynesia, 132082, 138682

New Caledonia, 125322, 125548

New Zealand, 2223281, 2144855

Papua New Guinea, 3359979, 3498287

Solomon Islands, 259909, 278239

Vanuatu, 117573, 122078

• Some program runs

Enter name of dataset: oceania.csv

dataset:

Country, Females, Males

Australia, 11175724, 11092660

Fiji, 421365, 439258

French Polynesia, 132082, 138682

New Caledonia, 125322, 125548

New Zealand, 2223281, 2144855

Papua New Guinea, 3359979, 3498287

Solomon Islands, 259909, 278239

Vanuatu, 117573, 122078

header:

['Country', 'Females', 'Males']

data:

['Country', 'Females', 'Males']

['Australia', 11175724, 11092660]

['Fiji', 421365, 439258]

['French Polynesia', 132082, 138682]

['New Caledonia', 125322, 125548]

['New Zealand', 2223281, 2144855]

['Papua New Guinea', 3359979, 3498287]

['Solomon Islands', 259909, 278239]

['Vanuatu', 117573, 122078]

Enter name of dataset: elevations.csv

dataset:

Location, Author, Max Height, Min Height

Narnia, Lewis, 4810, -10

Neverland, Milne, 426, -2

Oz, Baum, 1231, 679

Sleepy Hollow, Irving, 1629, 304

Stars Hollow, Sherman-Palladino, 725, 152

Toyland, MacDonough, 6187, 0

Wonderland, Carroll, 5895, -5

header:

['Location', 'Author', 'Max Height', 'Min Height']

data:

['Narnia', 'Lewis', 4810, -10]

['Neverland', 'Milne', 426, -2]

['Oz', 'Baum', 1231, 679]

['Sleepy Hollow', 'Irving', 1629, 304]

['Stars Hollow', 'Sherman-Palladino', 725, 152]

['Toyland', 'MacDonough', 6187, 0]

['Wonderland', 'Carroll', 5895, -5]

---

Program what_day_is_it.py

• Analyze how President's day is and is not celebrated.

• Data set of interest: wdii.csv

ID, State, GWBD, When

AK, Alaska, Presidents' Day, 3rd Monday in February

AL, Alabama, George Washington-Thomas Jefferson Day, 3rd Monday in February

AR, Arkansas, George Washington's Birthday and Daisy Gatson Bates Day, 3rd Monday in February

AZ, Arizona, Lincoln-Washington-President's Day, 3rd Monday in February

CA, California, President's Day, 3rd Monday in February

CO, Colorado, Presidents' Day, 3rd Monday in February

CT, Connecticut, Washington's Birthday, 3rd Monday in February

DE, Delaware, No holiday observed, Non-applicable

FL, Florida, No holiday observed, Non-applicable

GA, Georgia, Washington's Birthday, Day before Christmas

....

IN, Indiana, Washington's Birthday, Near Christmas or Thanksgiving

....

VA, Virginia, Washington's Birthday, 3rd Monday in February

....

• Task

• For a user-specified web source dataset counts the number of rows, where for a user-specied column of interest label, the column value equals a user-specified value key

Algorithm

• What should it be?

Some sample program runs

Enter name of dataset: wdii.csv

Enter column of interest: GWBD

Enter column value of interest: No holiday observed

9

Enter name of dataset: wdii.csv

Enter column of interest: When

Enter column value of interest: 3rd Monday in February

38

---

Summarizing

• If you are only analyzing the dataset, then the easiest way of accessing the dataset.

dataset = ... # get the dataset

... # set up dataset processing

for row in dataset : # consider rows one by one

  # process current row of the dataset

  ... # process the row

... # finish off dataset

• There are two basic ways of analyzing the individual cells in a dataset. Generally use the first way unless column index manners.

dataset = ... # get the dataset

... # set up dataset processing

for row in dataset : # consider rows one by one

  # process current row of the dataset

  ... # prepare to process the cells

  for cell in row : # consider cells of the row one by one

  # process the current cell for the row

  ... # process the cell

  ... # finish off row analysis

... # finish off dataset analysis

dataset = ... # get the dataset

for row in dataset : # consider row one by one

  # process current row of the dataset

  nbr_columns = len( row ) # get number of columns in current row

  ... # prepare to process row's cells

  # process the cells of the current row

  for c in range( 0, nbr_columns ) : # consider row's column indices one by one

  # process cell at row[ c ]

  cell = row[ c ] # pick off the cell of the row

  ... # process the cell

  ... # finish off row analysis

... # finish off dataset analysis

• Create a copy of a column of a dataset

dataset = ... # get the dataset

c = ... # get the column index

column_copy = [] # need a cell accumulator

for row in dataset : # consider rows one by one

  # get cell from row's column c

  cell = row [ c ] # get the cell in column c

  column_copy.append( c ) # copy the cell into accumulator

... # analyze the column

---

 

---

🦆 © 2022 Jim Cohoon

Resources from previous semesters are available.