Kotlin for android developers

1. Introduction

1.1 What is Kotlin

Kotlin is very intuitive and easy to learn for Java developers
We have total integration with our dialy IDE for free
It's more expressive
It's safer
It's functional
It makes use of extension functions
It's highly interoperable

1.2What do we get with Kotlin

Expresiveness
Null Safety
...

2. Getting ready

3. Creating a new project

18 Collections and functional

18.1 Aggregate operations

any: return true if at least one element matches the given predicate
all: return true if all the elements match the given predicate
count: return the number of elements matching the given predicate
fold: accumulates the value starting with an initial value and applying an operation from the first to the last element in collection
foldRight: same as fold,but it goes from the last to element to first
forEach: performs the given operation to each element.
forEachIndexed: same as forEach, though we also get the index of the element
max:returns the largest element or null if there no elements
maxBy: return the first element yielding the largest value of the given function or null if there are no elements.
min: returns the smallest element or null if there are no elements
minBy: returns the first element yielding the smallest value of the given function or null if there are no elements
none: return true if there no elements match the given predicate
reduce: same as fold,but it does't use an initial value.It accumulates the value applying an operation from the first to the last element in a collection
reduceRight: same as reduce,but it goes from the last element to first
sumBy: returns the sum of all values produced by the transform function from the elements in the collection

18.2 filtering operation

drop: returns a list containing all elements except first n elements
dropWhile: returns a list containing all elements except first elements that satisfy the given predicate.
dropLastWhile: returns a list containing all elements excepting the last that satisfy the given predicate.
filter: returns a list containing all elements matching the given predicate
filterNot: returns a list containing all elements not matching the given predicate
filterNotNull returns a list containing all elements that are not null
silce: returns a list containing elements at specified indices
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