The errata list is a list of errors and their corrections that were found after the product was released.
The following errata were submitted by our customers and have not yet been approved or disproved by the author or editor. They solely represent the opinion of the customer.
| Version |
Location |
Description |
Submitted by |
Date submitted |
| ePub |
Page cover page
cover image |
phenomenon:
the cover image is not shown with the iBooks app on the iOS and in the file property information of the finder on the OSX.
confirmed version:
Learning Scala.epub - meta property "dcterms:modified" = 2014-10-14T17:49:33Z
under iOS 7.1.2 and iBooks 3.2 (2083)
cause:
no cover-image property found in the item element of "content.opf" file.
at line 73 in content.opf
<item id="cover-image" href="images/orm_front_cover.png" media-type="image/png"/>
expected:
line 73 should be following a line.
<item id="cover-image" properties="cover-image" href="images/orm_front_cover.png" media-type="image/png"/>
|
Anonymous |
Oct 21, 2014 |
| ePub |
Page Table 6-6
Table 6-6 |
The description of the mkString method in table 6-6 says that it renders a collection to a set. It actually creates a string.
|
Matthew Halverson |
Jul 12, 2016 |
| Other Digital Version |
Kindle location 2705 of 6135, Table 7-2. Sequence Types |
TYPO technical error in Table 7-2. Sequence types: In the Queue listing Description the Queue is described as “a first-in-last-out” list. This should read, as the abbreviation in the table suggests, a first-in-first-out (FIFO) sequence.
|
Tom Pittard |
Jun 26, 2017 |
| Printed |
Page 7
2nd paragraph |
Exercise 5 suggests using :paste -raw
But if I paste in the following line
println("Hello world.")
I get the following:
// Exiting paste mode, now interpreting.
<pastie>:1: error: expected class or object definition
println("Hello world.")
^
There were compilation errors!
However, if I just use :paste everything works as expected.
|
John Langley |
Apr 06, 2015 |
| PDF |
Page 15
Table 2-1 |
Byte range is -128 to 127, not -127 to 128.
|
Anonymous |
Feb 24, 2018 |
| Printed |
Page 22
line -14 |
"indicates they they are"
should read
"indicates that they are"
|
roakonam |
Feb 23, 2015 |
| Printed |
Page 26
The fifth paragraph |
Nothing important: a spelling error only:
The word "development" is spelled as "developemnt"
I want the book to be perfect so I will signal all tiny and perhaps more important problems as I continue reading.
|
Andrew Jonca |
Jan 10, 2015 |
| Mobi, Other Digital Version |
Page 37%
Table 6-5 |
I'm using the Kindle book. In this table, the first row, second column has the following text duplicated:
"reduction function."
|
Kevin D'Elia |
Jan 05, 2015 |
| Printed |
Page 39
first line of code |
the first line of code on this page:
for (day <- res0) print(day + ", ")
refers to dynamically generated variable res0. However, on page 38 where this variable is generated, it is referred to as res10.
|
Gino Fortunato |
Dec 25, 2019 |
| Mobi, Other Digital Version |
Page 40%
Exercises |
This really has to do with the exercises for Chapter 6. I found other typos that I will list in a later errata report. Here's the one for exercise #4:
def longest(l: List[String]): String = names.sortBy(0 - _.size).head
Since names isn't defined yet, REPL barfs at this def. And, it should actually be "l", not "names", as "l" is the parameter to the function.
The other examples for this exercise also have "names" as the list val.
Side comment: I have been trying to learn Scala for a few weeks now; this book, not only because of the clear writing and organization of the material, but also because of the excellent exercises and explanations, has had the most significant positive impact on my progress. Great job, Jason!
|
Kevin D'Elia |
Jan 05, 2015 |
| Other Digital Version |
50%
OpenWeatherMap API example |
I'm using the Kindle edition but the example is in all versions. It is also elsewhere as an example to follow in the exercises.
It looks like the API has changed and you have to sign up for a free account before you can use it. This also means you need to pass in your API key when using the API itself. It would be a simple change to update the code and explain to the reader that this would need to be done beforehand. Currently, the API responds with an Unauthorised Access error and the code never returns the Future you're demonstrating.
|
Steve Godrich |
Nov 03, 2016 |
| PDF |
Page 70
code line annotated with "3" |
val maximize is redefined by using a function literal. However, this is now allowed for 2 reasons: first, as it already exists, a second use of val generates an error. Moreover, when omitting it, since the original maximize is also a val, redefinition is not allowed.
Fix: the first maximize should be a var, and for the second, the "val" should be omotted
|
Anonymous |
Apr 12, 2019 |
| ePub |
Page 71
1st paragraph |
Typo: ...and the println was trigggered.
|
Anonymous |
Oct 15, 2017 |
| Printed |
Page 92
Last paragraph |
This is not important.
Towards the end of the page, the text explains that a map method maps the items of a list to the items of another list that "has the same size as the first."
It sounds correct, but unfortunately some of the map methods as it calls them do not seem to fit that description. In fact, in the examples coming up in the next page (p. 93), the size of the resulting lists for the collect and flatmap methods is different from the original.
|
roakonam |
Feb 23, 2015 |
| PDF, ePub |
Page 99
Table 6-6 |
The description of the mkString method in table 6-6 says that it renders a collection to a set. It actually creates a string from the collection.
This MAY also be in the printed version, but I am still waiting for the copy that I have ordered, so can't check right now.
|
Anonymous |
Jul 12, 2016 |
| Printed |
Page 111
Line 13 |
As the paragraph is to explain how to use a builder for a collection type, which may or may not be a Set, the term "Set" here should be replaced with something like "collection" :
"convert it back to the final Set."
|
roakonam |
Feb 26, 2015 |
| Printed, PDF, ePub |
Page 114
Table 7-2. Sequence types |
In Table 7-2. Sequence types it is written that
Queue A first-in-last-out (FIFO) list.
Well it should be
Queue A first-in-first-out (FIFO) list.
|
Anonymous |
Aug 25, 2015 |
| Printed |
Page 139
1st paragraph |
Given the following code in the book:
"""
class User(n: String) {
val name: String = n
def greet: String = s"Hello from $name"
override def toString = s"User($name)"
}
"""
The paragraph says:
"""
The class parameter "n" is used here to initialize the "name" value. However, it could not be used inside either of the methods. Class parameters are available for initializing fields (values and variables in a class) or for passing to functions, but once the class has been created the parameters aren't available.
"""
This is incorrect. Class parameters are available everywhere within the class, including in the methods it owns: greet and toString. So this does work:
"""
class User(n: String) {
def greet: String = s"Hello from $n"
override def toString = s"User($n)"
}
"""
What the author probably means is that class parameters aren't available outside (instead of inside) the class, unless they are fields:
"""
val u = new User("abc")
println(u.n) // doesn't work because its only a class parameter and not a field (without "val")
println(u.name) // does work, because its a field
"""
|
Jesse |
Apr 11, 2016 |
| PDF |
Page 142
5nd paragraph, starts with "You can invoke a class's..." |
The sentence, "This action, of reversing memory to allocate a class's contents", might be "This action, of reserving memory to allocate a class's contents".
reversing -> reserving.
|
sandbox wang |
Jul 09, 2017 |
| Printed |
Page 157
Lines 16-19 |
The package syntax is nested, but probably that is not meant be here, since the nested syntax is illustrated towards the end of the page, i.e., the same code repeats there as it stands.
So the code in Lines 16 to 20 should be replaced with the one not nested, more like the one that appears in p. 160, though not exactly the same:
package com.oreilly{
class Config(val baseUrl: String = "http://localhost")
}
|
roakonam |
Feb 26, 2015 |
| PDF |
Page 179
3rd paragraph |
In the 3rd paragraph: ..., so the traits are convering an RGB ...
Should be: ..., so the traits are converting an RGB ...
The typo for "convering" to "converting".
|
Anonymous |
Nov 30, 2015 |
| Printed |
Page 188
Bullet Point 3 |
The line at Bullet Point 3 should be:
"org.scalatest" %% "scalatest_2.11" % "2.2.1" % "test"
to reflect the comment on the top of next page.
|
Anonymous |
Nov 17, 2015 |
| Printed |
Page 201
|
Line 10
An excess close parenthesis should be removed from:
"(1, 2, true))"
|
roakonam |
Mar 01, 2015 |
| Printed |
Page 217
Line -8 |
"becuase" should read "because"
|
roakonam |
Mar 01, 2015 |