Data Analyst

Question 1

Що таке генеральне середнє?

Answer 1

це середнє арифметичне варіант ознак

1/N * (sum(xi)) N - об’єм генеральної суккупності

Question 2

How to read csv file? [Pandas]

Answer 2

import pandas as pd

data = pd.read_csv(‘path_name’, sep=’;’)

Question 3

Get first / last n rows in data? [pandas]

Answer 3

data. head(5)

data. tail(5)

Question 4

How to replace NaN with zeroes? [pandas]

[2 options]

Answer 4

data. replace(np.nan, 0)

data. fillna(0)

Question 5

How to convert column to float? [pandas]

Answer 5

dataset[column_name] = dataset[column_name] \
.str.replace(‘,’, ‘.’) \
.astype(float)

Question 6

How to sort rows by some columns? [pandas]

Answer 6

dataset.sort_values(by=[sortBy], ascending=False)[[‘Country Name’, sortBy]]

Question 7

How to find max element (its index) in data? [pandas]

how we can get that row?

Answer 7

data[‘Area’].idxmin()

data.iloc[ind_min_area][0]

Question 8

How to replace nan with column mean? [pandas]

Answer 8

data.replace(np.nan, data.mean())

Question 9

How to count total amounts for each values? [pandas]

Ex: T T K -> T = 2 K = 1

Answer 9

data[‘Populatiion’].value_counts()

Question 10

How to group by? [pandas]

Answer 10

groupedData = data.groupby(‘Region’)[‘Area’].mean()

print(str(groupedData.idxmax()) + ‘ that has ‘ + str(groupedData.max()))