Pandas

Question 1

How to create a DataFrame and a Series?

Answer 1

pd. DataFrame({“Bob”:[0,3,9], “Tim”:[1,2,3]}, index=[“Product A, Product B])
pd. Series([3,5,6,7], index=[“Product A, Product B])

Question 2

How to let a column become the index?

Answer 2

object.set_index(“column name”)

Question 3

Read in csv if csv has index itself:

Answer 3

…, index_col=0

Question 4

Acess column:

Answer 4

object[“column”]

Question 5

Acess with loc and iloc:

Answer 5

loc (needs column name) and iloc (both row, column): object.iloc[3,6] or object.loc[5, “houses”]

Question 6

How large is DF:

Answer 6

object.shape

Question 7

Assigning data

Answer 7

reviews[“critics]=”everyone”

Question 8

Acess specific value:

Answer 8

object[“column”] [2]

Question 9

Set up condition:

2 Conditions:

Answer 9

reviews. loc[reviews.country==”Italy”]

reviews. loc[(reviews.country==”Italy”) & reviews.points < 90)]

Question 10

Multi Index: which p.e. occurs when you have filtered with 2 columns

Answer 10

object.reset_index()

Question 11

How to sort by values and how to sort by index?

Answer 11

object.sort_values(by=”column name”, ascending=False). For 2 or more: list with column names.
Object.sort_index()= to sort by index values

Question 12

How to ask for a datatype and how to transform one?

Answer 12

Object.column.dtype= to ask
Object.column.astype(“…”) = to transform

Question 13

How to rename a column or an index?

Answer 13

object. rename(columns={“points”: “score”})

object. rename(index={0: “first”, 1: “second”})

Question 14

Combine DataFrame and/or Series?

How if index in common?

Answer 14

pd.concat([object 1, object 2]) if same columns

left=canada_yt.set_index([“title”, “trending”])
right=usa_yt.set_index([“title”, “trending”])
left.join(right, lsuffix=”_can”, rsuffix=”_usa”)
->suffixe are only necessary because there are same column names in bith datasets