The Syllabus has this section which says;

Data science community

1. Attend data science society at least once during the semester.
2. Register to get a regular email on topics related to data science.

Interview Question: What do you do to stay up with the current methods in data science?

Don’t Say: Nothing

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The data science workflow

• You are going to hit SHIFT + ENTER thousands of times.
• We don’t usually source our scripts.
• Think of Python Interactive like a TI-86 or Excel on steroids.
• You code in pieces.
• Rewrite for clarity!

df = pd.DataFrame(
{"a" : [4 ,5, 6],
"b" : [7, 8, 9],
"c" : [10, 11, 12]})
# Can someone read this code in english?

Use the cheat sheet to find the functions you would need to implement the following steps.

I want to;

1. sort my table by column a then
2. only use the first 2 rows then
3. calculate the mean of column b.

I want to;

1. rename column a to duck then
2. subset to only have duck and b columns then
3. keep all rows where b is less than 9 then
4. find the min of duck

Pandas and Altiar are built to allow for method chaining.

• Altair is a chart object
• pandas is a DataFrame object
• We usually include () around our entire method so we can show it in steps.

flights_url = "https://github.com/byuidatascience/data4python4ds/raw/master/data-raw/flights/flights.csv"
flights = pd.read_csv(flights_url)
flights['time_hour'] = pd.to_datetime(flights.time_hour, format = "%Y-%m-%d %H:%M:%S")

(flights
    .filter(['dep_time'])
    .assign(
      hour = lambda x: x.dep_time // 100,
      minute = lambda x: x.dep_time % 100
      ))

url = "https://github.com/byuidatascience/data4python4ds/raw/master/data-raw/mpg/mpg.csv"

mpg = pd.read_csv(url)

chart_loess = (alt.Chart(mpg)
  .encode(
    x = "displ",
    y = "hwy")
  .transform_loess("displ", "hwy")
  .mark_line()
)

chart_loess