Ruby - Difference between Array#<< and Array#push
RubyArraysAppendRuby Problem Overview
From examining the documentation for Ruby 1.9.3, both Array#<< and Array#push were designed to implement appending an element to the end of the current array. However, there seem to be subtle differences between the two.
The one I have encountered is that the * operator can be used to append the contents of an entire other array to the current one, but only with #push.
a = [1,2,3]
b = [4,5,6]
a.push *b
=> [1,2,3,4,5,6]
Attempting to use #<< instead gives various errors, depending on whether it's used with the dot operator and/or parentheses.
Why does #<< not work the same way #push does? Is one not actually an alias for the other?
Ruby Solutions
Solution 1 - Ruby
They are very similar, but not identical.
<< accepts a single argument, and pushes it onto the end of the array.
push, on the other hand, accepts one or more arguments, pushing them all onto the end.
The fact that << only accepts a single object is why you're seeing the error.
Solution 2 - Ruby
Another important point to note here is that << is also an operator, and it has lower or higher precedence than other operators. This may lead to unexpected results.
For example, << has higher precedence than the ternary operator, illustrated below:
arr1, arr2 = [], []
arr1.push true ? 1 : 0
arr1
# => [1]
arr2 << true ? 1 : 0
arr2
# => [true]
Solution 3 - Ruby
The reason why << does not work and push does is that:
pushcan accept many arguments (which is what happens when you do*b).<<only accepts a single argument.
Solution 4 - Ruby
The main difference between Array#<< and Array#push is
Array#<< # can be used to insert only single element in the Array
Array#push # can be used to insert more than single element in the Array
Another significant difference is, In case of inserting single element,
Array#<< is faster than Array#push
Benchmarking can help in finding out the performance of these two ways, find more here.
Solution 5 - Ruby
The push method appends an item to the end of the array.It can have more than one argument.
<< is used to initialize array and can have only one argument , adds an element at the end of array if already initialized.