Starting out with Python: Chapter 7 - List and Tuples

Tuples doesn't have the following

- append() - remove() - reverse() - insert() - sort() Mnemonic ar-rist (like artist, except no t, - to indicate a second r)

Properties of tuples

- supports indexing - methods such as index() - built-in functions such as len, min and max - Slicing expressions - in operator - the + and * operators

Why tuples vs list?

- tuples are processed faster (tuple is fixed-size 1 block and list are 2 blocks, the object and variable-size for elements) - safe since modification is not allowed

Two types of sequences in pythons

1. Lists 2. Tuples

What sort of graph does the plot function produce?

A line raph

element

each item stored in list

Module

files with the ". py" extension containing Python code that can be imported inside another Python Program

The importing as statement

import matplotlib.pyplot as plt plt.method() you can use the plt object vs having to write matplotlib.pyplot().method() everytime

Finding items in a list with the in Operator

item in list

slice

items taken from a sequence

list concatenation

joining lists with the + operator example 1 list3 = list1 + list2 example 2 list1 += list2

Tuple

like a list except immutable meaning values can't be changed

Convert list into a tuple

list = [elements] list = tuple(list) <- answer right here

How to create pie chart in Python

list = [values] plt.pie(list)

Repetition operator

makes multiple copies of a list and joins them together syntax list * n

Syntax, create tuple with x number of elements

my_tuple(x,) whatever x is, there will be that number of elements. x must be an integer

Generating a list with range(x, y, z) function

numbers = list(range(1, 10, 2)) 1: starting point 10: ending point 2: step value the list is [1, 3, 5, 7, 9]

Generating a list with the range() function

numbers = list(range(5)) The list is [0, 1, 2, 3, 4]

How to plot bar charts

plt.bar(left_edges, heights) - left_edges are the actual bars themselves and will align towards the left part of the x-axis tick - height is the height of the bar

How to plot bar chart specifying bar width

plt.bar(left_edges, heights, bar_width)

Bar color codes

plt.bar(left_edges, heights, color=('r', 'g', 'b', 'w', 'k')) - first bar is red - second bar is green - third bar is blue - fourth bar is white - fifth bar is black

Marker symbol codes

plt.plot(x_coordinates, y_coordinates, 'marker symbol')

Customizing the X and Y axes

plt.xlim(xmin=1, xmax=100) modifies min and max values for the x axes replace the x with a y to do the same for the y axes.

What functions do you use to add X and Y axes labels in a graph?

pyplot.xlabel(X_LabelName) pyplot.ylabel(Y_LabelName)

matplotlib

python *package for plotting data*

Repetition operator question what's the output of numbers = [0] * 5 print(numbers)

the [0] is the list the 5 shows how many copies to make of the elements in the list therefore the output will be [0, 0, 0, 0, 0]

Default x-axes and y-axes

the graph will show both x and y min and max values. x_coord = [0, 1, 2, 3, 4] The min shown will be 0 The max shown will be 4

to create a pie chart with the pie function, what argument must you pass?

the x and y coordinates

Convert tuple into list

tuple = (elements) tuple = list(tuple) <- answer right here

List and mutability

values within a list are able to be changed

Indexing a list

when you access an element within the list like so

To create a graph with the plot function, what two arguments must you pass?

x and y coordinates are needed recall you also need import matplotlib.pyplot() as plt

How do you change the lower and the upper limits of the X and Y axes in a graph?

xlim(xmin, xmax) ylim(ymin, ymax)

How do you customize the tick marks along the X and Y axes in a graph?

xticks(tick_list [elements], labels_list[elements]) yticks(tick_list [elements], labels_list[elements])

Can list have different data types?

yes

List vs Tuples

Lists are mutable (can be changed) and tuples are immutable (can't be changed)

pyplot

Module in matplolib, needed to create graphs import matplotlib.pyplot

What is a pie chart slice label?

What's underlined A label for each portion of the pie chart

sequence

an object that contains items of data

List

an object that contains multiple data items