Let's say that we have an array of 6 numbers and we need to double all those numbers.
Here is how we can do that.
Ruby provides method map which can help us to this in a much simpler way.
First let's see how to use map.
Notice that how much shorter the code is with map.
map internally builds an array for us and that's why
we don't need to build an array. All we need to do is to tell map
how to calculate the new value that will go into the array.
In this case we are multiplying each element with 2.
Let's see one more example.
We have an array full of strings and we need to make the first letter a capital letter.
First let's see how we can do it by keeping an array outside and then adding to the array ourselves.
We can solve this using map like this.
If the code in the block is of only one line then the code can be written like this.
Now you can see that using map the code becomes much simpler.
Notice that when we are using map then all the things that we do not need to do.
- We do not need to create a new array.
- We do not need to push the values to this new array.
- We do not need to return this new array.
All this work is done by map and that means we need to do less work.
By using map we end up with less work and hence less amount of code.
Next time if you are creating an array for the sole purpose of collecting
transformed value then pause and think if you could use map in that scenario.