For example an array contains the following contents a 1 1 2 5 6 1 2 8 i want to know the indices of all the ones present in that array.
Ruby array find all indexes.
Find l l.
Here is a quick example.
Returns a new array.
Since everything in ruby evaluates to true except for false and nil using all.
The select method works in a similar way but it constructs a new array containing all of the elements that match.
Block condition to follow return.
If a block is given instead of an argument returns the index of the first object for which the block returns true.
Index value of the array elements.
Array indexing starts at 0 as in c or java.
Owner myself match index list.
When the block is omitted all.
A negative index is assumed relative to the end of the array that is an index of 1 indicates the last element of the array 2 is the next to last element in the array and so on.
Testing arrays for nils with enumerable all.
A variable can hold only one item at a time.
Ruby arrays can hold objects such as string integer fixnum hash symbol even other array objects.
The block usage was added in 1 8 7 so to get the same functionality in an earlier version of ruby you need to utilize the find method.
The second form creates a copy of the array passed as a parameter the array is generated by calling to ary on the parameter.
To access a specific item or element of an array you reference its index or its position in the array.
Using block version in ruby 1 8 7.
Without a block on an array is effectively a test to see if all the items in the collection evaluate to true or conversely if there are any false or nil values in the array.
Uses this implied block.
So to retrieve the first element from our emails array we append the element s index to the variable using square brackets like this.
Find index is a array class method which returns the index of the first array.
Arrays are zero based.
The index of the first element is zero.
Arrays can hold objects of any data type.
In ruby indexes start at zero.
When a size and an optional default are sent an array is created with size copies of default take notice that all elements will reference the same object default.
These items are called elements of the array.
Arrays can hold multiple items.
Each element can be referred to by an index.
If it doesn t find anything after iterating through all of the elements it returns nil.
By running the following you can achieve that.
In the first form if no arguments are sent the new array will be empty.
It is actually not that difficult to do so.
If the last expression in the block evaluates to true the find method returns the value and stops iterating.
