Chapter03_Plotting

Question 1

for what is the function
ax1 = fig.add_subplot(2,2,1)
used? Describe the parameters of the function call

Answer 1

used to create subplots in a figure. The parameters are
1. Numbers of rows in the grid
2. Number of columns in the grid
3. The position of the subplot within the grid

Question 2

describe the parameter of the function call plt.plot(rng.standard_normal(50).cumsum(),’k–’)

Answer 2

1. rng.standard_normal(50): generate an array of the cumulative sum of a normal distributed array of 50 elements
2. ‘k–’ : style of plot line as dashed black line

Question 3

fig = plt.figure()
ax1 = fig.add_subplot(2,2,1)
ax2 = fig.add_subplot(2,2,2)
ax3 = fig.add_subplot(2,2,3)
rng = np.random.default_rng()
plt.plot(rng.standard_normal(50).cumsum(),'k--')
ax1.hist(rng.standard_normal(100),bins=20,color='k',alpha=0.3)
ax2.scatter(np.arange(30),np.arange(30)+3*rng.standard_normal(30))

Describe the position of each plots:

Answer 3

plt.plot(rng.standard_normal(50).cumsum(),'k--') : the dashed line will be ploted at ax3, position 3, left bottom

ax1.hist(rng.standard_normal(100),bins=20,color='k',alpha=0.3) : the histogram will be ploted at position one, left top

ax2.scatter(np.arange(30),np.arange(30)+3*rng.standard_normal(30)) : will be ploted at position 2, right top

Question 4

What is a scatter plot?

Answer 4

display individual data points in a two-dimension space, x and y axis.

Question 5

Descibe the parameters of the function call ax2.scatter(np.arange(30),np.arange(30)+3*rng.standard_normal(30))

Answer 5

1. x coordinates as integer numbers from 0 to 29
2. y coordinates as integer numbers from 0 to 29 summed elementwise by 3 times the elements of an normal distributed array of 30 elements

Question 6

readjust the size of a figure plot ‘figure’ to width 20 inches and heigh 40 inches

Answer 6

plt.rc(‘figure’, figsize=(20, 40))

Question 7

what does the functiona call do? what is the return? plt.subplots(1,2, sharey=True)

Answer 7

returns a figure and list of subplots:
* first parameter number of rows
* second parameter number of columns
* sharey=True : subplots share the same y

Question 8

how to define the x and y axis for plt.plot ?

Answer 8

define x and y as list an pass them to plt.plot(x,y)

Question 9

how to create a numpy array from price stock saved in data to store the lowest price up to respective index at each possible index?

Answer 9

np.minimum.accumulate(data)

Question 10

what is the type of result of np.where(condition1 & condition2) ?

Answer 10

tuple, whereas first element with the indices, for which condition1 & condition2 match

Question 11

what does the function sns.pairplot() do?

Answer 11

it creates a matrix of histrograms and scatterplots containing all possible pairs od columns from a given DataFrame