#set document(title: "10.6 Chapter summary", author: "OpenStax / XYZ Homework") #set page(width: 8.5in, height: auto, margin: 1in) #import "@preview/cetz:0.5.2" #set text(font: ("STIX Two Text", "Libertinus Serif", "New Computer Modern"), size: 10.5pt, lang: "en") #show math.equation: set text(font: ("STIX Two Math", "New Computer Modern Math")) #set par(justify: true, leading: 0.62em, spacing: 0.9em) #set enum(spacing: 1.1em) // room between list items so tall inline fractions don't collide #set list(spacing: 1.1em) #set table(stroke: 0.5pt + rgb("#c7ccd3")) #let BLUE = rgb("#183B6F") // brand navy — section bars + example/solution labels (white on navy 11.09:1) #let ORANGE = rgb("#A94509") // brand primary-700 — AA-safe deep orange for TEXT (5.93:1 on white; raw brand #F37021 is 2.94:1 and must never carry text) #let RED = rgb("#DC2626") // brand error-600 #let GREEN = rgb("#059669") // brand success-600 (decoration only; small green text uses green-text #007942) #show heading.where(level: 1): it => block(width: 100%, above: 0pt, below: 16pt, fill: gradient.linear(BLUE, rgb("#2C5AA0")), inset: (x: 14pt, y: 12pt), radius: 3pt, text(fill: white, weight: "bold", size: 19pt, it.body)) #show heading.where(level: 2): it => block(width: 100%, above: 18pt, below: 10pt, fill: BLUE, inset: (x: 10pt, y: 6pt), radius: 2pt, text(fill: white, weight: "bold", size: 12pt, it.body)) #show heading.where(level: 3): it => text(fill: ORANGE, weight: "bold", size: 12.5pt, it.body) #show heading.where(level: 4): it => text(fill: BLUE, weight: "bold", size: 10.5pt, it.body) #let examplebox(label, title, body) = block(width: 100%, breakable: true, fill: rgb("#EFF1F5"), stroke: 0.5pt + rgb("#CFDDF0"), radius: 4pt, inset: 10pt, above: 12pt, below: 12pt)[ #block(below: 6pt)[#box(fill: BLUE, inset: (x: 6pt, y: 2pt), radius: 2pt, text(fill: white, weight: "bold", size: 8.5pt, label)) #h(0.4em) #strong[#title]] #body] // rail = decorative left rule (raw brand token); labelcolor = AA-safe label text shade #let notebox(label, rail, labelcolor, tint, body) = block(width: 100%, breakable: true, fill: tint, stroke: (left: 3pt + rail), inset: (left: 10pt, rest: 8pt), radius: (right: 4pt), above: 11pt, below: 11pt)[ #text(fill: labelcolor, weight: "bold", size: 7.5pt, tracking: 0.5pt)[#upper(label)] #linebreak() #body] #let solutionbox(body) = block(above: 4pt, below: 8pt)[ #text(fill: BLUE, weight: "bold", size: 8.5pt)[Solution] #linebreak() #body] #let figph(msg) = block(width: 100%, height: 60pt, fill: rgb("#f6f7f9"), stroke: (paint: rgb("#c7ccd3"), dash: "dashed"), radius: 4pt, inset: 10pt)[ #align(center + horizon, text(fill: rgb("#889"), style: "italic", size: 9pt, msg))] // Standardize inlined figure sizes: measure the natural CeTZ canvas, then scale to a // consistent envelope (aspect-aware; see build_typst.py FIG_* constants). Unlike the // print preamble, dimensions are FLOORED: in an editor a user can trim a figure to a // degenerate 1-D shape (a bare line), and w/h or tw/w would then divide by zero. #let _STD_W = 3.5 #let _WIDE_W = 5.6 #let _MAX_H = 3.4 #let _ASPECT_WIDE = 2.2 #let _UPSCALE_MAX = 1.15 #let stdfig(body) = context { let m = measure(body) let w = calc.max(m.width / 1in, 0.01) let h = calc.max(m.height / 1in, 0.01) let tw = if w / h > _ASPECT_WIDE { _WIDE_W } else { _STD_W } let s = calc.min(tw / w, _MAX_H / h, _UPSCALE_MAX) align(center, box(scale(x: s * 100%, y: s * 100%, reflow: true, body))) } #show figure: set block(breakable: false) #set figure(gap: 8pt) #show figure.caption: set text(size: 8.5pt, fill: rgb("#555")) == 10.6#h(0.6em)Chapter summary Highlights from this chapter include: - A dictionary in Python is a container object including key-value pairs. - The dict type implements a dictionary in Python. - A dictionary cannot have duplicate keys. - A dictionary is a mutable object but keys in the dictionary must be immutable objects. - A dictionary can be created using curly braces or the dict() method. - Values in the dictionary can be obtained through square bracket notation or the get() method. - Dictionary items, keys, and values can be obtained using items(), keys(), and values() methods, respectively. - Existing items can be modified or new items can be added to a dictionary using square brackets notation or the update() method. - Items can be removed from a dictionary using the del keyword or the pop() method. - Conditional statements can be used with a dictionary to check if the dictionary contains specific keys, values, or key-value pairs. - Looping on a dictionary can be done by iterating over keys, values, or items. - Nested dictionaries are dictionaries that are stored as values within another dictionary. - With dictionary comprehension, elements of an iterable object are transformed into key-value pairs. At this point, you should be able to use dictionaries in your programs. The programming practice below ties together most topics presented in the chapter. #figure(table( columns: 2, align: left, inset: 6pt, table.header([Concept], [Description]), [Dictionary creation using curly braces], [my\_dict = {key1:value1, key2:value2}], [Dictionary creation using the dict() method], [\# Using a list my\_list = \[(key1, value1), (key2, value2)\] my\_dict = dict(my\_list) \# Using keyword arguments my\_dict = dict(key1=value1, key2=value2) \# From another dictionary old\_dict = {key1: value1, key2: value2} new\_dict = dict(old\_dict)], [Accessing dictionary items], [my\_dict = {key1: value1, key2: value2} \# Accessing item using square bracket notation my\_dict\[key1\] \# Accessing item through get() method my\_dict.get(key1)], [Accessing all dictionary items], [my\_dict.items()], [Accessing all dictionary keys], [my\_dict.keys()], [Accessing all dictionary values], [my\_dict.values()], [Adding a new key-value pair or updating an existing key-value pair], [my\_dict = {key1: value1, key2: value2} \# Updating an item using square bracket notation my\_dict\[key1\] = new\_value \# Adding a new key-value pair using square bracket notation my\_dict\[key3\] = value3 \# Updating an item using update() method my\_dict.update({key1: new\_value}) \# Adding a new key-value pair using update() method my\_dict.update({key3: value3})], [Deleting a key-value pair from a dictionary], [my\_dict = {key1: value1, key2: value2} \# Using del keyword del my\_dict\[key1\] \# Using pop() method deleted\_value = my\_dict.pop(key1)], [Iterating over a dictionary], [for key in dictionary: \# Loop expression   \# Statements to execute in the loop \#Statements to execute after the loop], [Nested dictionaries], [{ key\_1:{key11:value11, key12:value12}, key\_2:{key21:value21, key22:value22} }], [Dictionary comprehension], [{key\_expression: value\_expression for element in iterable}], )) #notebox("Note", rgb("#8a94a6"), rgb("#556666"), rgb("#f7f8fa"))[ #emph[Even and odd values] Given a list, create a dictionary with two keys, "even" and "odd". The values associated with each key must be the list of corresponding even and odd values in the given list. Input: input\_list = \[3, 5, 6, 1\] Prints {"even": \[6\], "odd":\[3, 5, 1\]} input\_list = \[1, 2, 3, 4, 5, 6, 7\] \# Create a dictionary my\_dict with two keys \# Print the content of the dictionary after the population ]