pandas

Question 1

import pandas library

Answer 1

import pandas as pd

Question 2

create a series in pandas

Answer 2

s = pd.Series([2,3,4,3], index=[‘a’,’b’,’c’,’d’])

Question 3

create a dataFrame in pandas

Answer 3

a = pd.DataFrame({‘a’ : [1,2,3], ‘b’ : [3,4,5]}, columns=[‘a’,’b’])

Question 4

read in csv in panadas

Answer 4

df = pd.read_csv(‘file.csv’)

Question 5

write dataframe to csv file

Answer 5

df.to_csv(‘/filepath/file.csv’)

Question 6

get value at a certain location given indices of row x col

Answer 6

a.iloc[[row], [col]]

Question 7

get value at a certain location given index and column names

Answer 7

a.loc[[row_name],[col_name]]

Question 8

Get values from series that are > 2

Answer 8

s[(s > 2)]

Question 9

get values from series equal to 2 or 3

Answer 9

s[(s == 3) | (s ==4)]

Question 10

get populations greater than 1million

Answer 10

df[df[‘population’] > 10000000]

Question 11

set series index a = 5

Answer 11

s[‘a’] = 5

Question 12

drop rows ‘a’ and ‘c’

Answer 12

s.drop([‘a’,’c’])

Question 13

drop column ‘population’

Answer 13

s.drop(‘population’, axis=1)

Question 14

sort the dataframe by population size

Answer 14

df.sort_values(by=’Population’)

Question 15

rank matrix positions

Answer 15

df.rank()

Question 16

get dataframe columns

Answer 16

df.columns

Question 17

get a sense of the dataframe with a single function – getting all count, mean, std, min, etc

Answer 17

df.describe()

Question 18

get rid of data that has null values

Answer 18

df.dropna(axis=0)