As a quick note today, if you ever need some examples of how the Kotlin collections methods work, I hope these examples are helpful.
First, here’s some sample data:
val a = listOf(10, 20, 30, 40, 10) val names = listOf("joel", "ed", "chris", "maurice")
As a quick note, here’s an example of how to use the Kotlin
sortedWith syntax with an anonymous function (lambda). Given this list of integers:
val list = listOf(7,3,5,9,1,3)
Here’s an example of how to use
sortedWith using a
Comparator and lambda:
As a quick note, here’s an example of the Kotlin
sortedBy syntax. Given this list of strings:
val names = listOf("kim", "julia", "jim", "hala")
the comments after these examples show how the Kotlin
sortedBy function works:
Here’s an example that shows how to find the largest files under a directory on MacOS and Linux/Unix systems.
A du/sort command to show the largest files under a directory on Mac OS X
The Unix/Linux command that worked for me on my MacOS system is this:
$ du -a * | sort -r -n | head -10
du is the disk usage command, and the
-a flag says, “Display an entry for each file in a file hierarchy.” Then I use the
sort command to sort the
du output numerically and in reverse. After that,
head -10 shows only the first ten lines of output. In the Music folder on my Mac the command and output look like this:
When I wrote the Scala Cookbook, I gave each recipe and then each chapter my full attention. I thought that if I wrote each recipe as well as possible, and included important recipes in each chapter, well, I wanted each chapter to be worth the price of the entire book. That was my goal.
As a result of this effort -- and perhaps to the chagrin of my editor -- the Scala collections chapters ended up being 130 pages in length.
I just noticed that some of the MySQL files on this website had grown very large, so I wanted to be able to list all of the files in the MySQL data directory and sort them by filesize, with the largest files shown at the end of the listing. This
ls command did the trick, resulting in the output shown in the image:
-S option is the key, telling the
ls command to sort the file listing by size. The
-h option tells
ls to make the output human readable, and
-r tells it to reverse the output, so in this case the largest files are shown at the end of the output.
This is an excerpt from the Scala Cookbook (partially modified for the internet). This is Recipe 11.28, “How to Use Sortable Sets in Scala”
You want to be able to store and retrieve items from a set in a sorted order.
To retrieve values from a set in sorted order, use a
SortedSet. To retrieve elements from a set in the order in which elements were inserted, use a
SortedSet returns elements in a sorted order:
This is an excerpt from the Scala Cookbook (partially modified for the internet). This is Recipe 11.23, “How to Sort an Existing Map by Key or Value”
You have an unsorted map and want to sort the elements in the map by the key or value.
Given a basic, immutable
This is an excerpt from the Scala Cookbook (partially modified for the internet). This is one of the shortest recipes in the book, Recipe 11.10, “How to Sort Arrays in Scala”
You want to sort the elements in an