I have a method which returns the number of hotels from a webpage:
hotel_count = self.getHotelsList.values
The output of this method is:
[["hotel_0", "hotel_1", "hotel_2", "hotel_3", "hotel_4", "hotel_5", "hotel_6", "hotel_7", "hotel_8", "hotel_9", "hotel_10", "hotel_11", "hotel_12", "hotel_13", "hotel_14", "hotel_15", "hotel_16", "hotel_17", "hotel_18", "hotel_19", "hotel_20", "hotel_21", "hotel_22", "hotel_23", "hotel_24", "hotel_25", "hotel_26", "hotel_27", "hotel_28", "hotel_29", "hotel_30", "hotel_31", "hotel_32", "hotel_33", "hotel_34", "hotel_35", "hotel_36", "hotel_37", "hotel_38", "hotel_39", "hotel_40"]]
I want to know the length of this array, but if I write
hotel_count = self.getHotelsList.values.length
The length is 1. How can I get a length of 41, which is the one I'm expecting?
Thanks
The array you are showing is nested inside another array. So the outer array is of length 1, the inner array is what you want.
To get it you have to first get the first element of the outer array using [0] or first
testList[0].length
testList.first.length
I am not sure why your getHotelsList method returns a nested array, it doesn't appear to need it.
hotel_count = getHotelsList.values.first.length
You can also do it with [0], but first is faster.
Two notes:
You don't need self at the beginning.
It is a bad habit to use camel case for method names in Ruby. it should better be get_hotels_list.
You could convert that into a single array with flatten:
hotel_count = self.getHotelsList.values.flatten.size
Related
Persoane = []
Nume = gets
Persoane.push Nume.split(",")
puts Persoane.sort
I am trying to get an user to input carachters that get split into substrings which get inserted in an array, then the program would output the strings in alphabetical order. It doesnt seem to work and I just get the array's contents, like so:
PS C:\Users\Lenovo\Desktop\Ruby> ruby "c:\Users\Lenovo\Desktop\Ruby\ruby-test.rb"
Scrie numele la persoane
Andrei,Codrin,Bradea
Andrei
Codrin
Bradea
PS C:\Users\Lenovo\Desktop\Ruby>
you can do this :
Nume = gets
puts Nume.split(",").sort
or in 1 line
array = gets.chomp.split(",").sort
The error is because of your use of push. Let's assume that you define the constant Nume by
Nume='Andrei,Codrin,Bradea'
Then, Nume.split(',') would return the Array ['Andrei', 'Codrin', 'Bradea']. When you do a Persoane.push, the whole array is added to your array Persoane as a single element. Therefore, Persoane contains only one Element, as you can verify when you do a
p Persoane
If you sort a one-element array, the result will also be just that one element - there is nothing to sort.
What you can do is using concat instead of push. This would result in Persoane being a 3-element array which can be sorted.
I'm not sure you need use constants here
If you don't need keep user input and use it somewhere, you can just chain methods like this
persons = gets.chomp.split(",").sort
For something a little different, let's not split at all.
people = gets.scan(/[^,]+/).map(&:strip).sort
This will avoid problems like multiple commas in a row yielding empty strings. Of course, you could also avoid that with:
people = gets.split(/\,+/).map(&:strip).sort
I am trying to insert data into Postgres. I have an array of data and I am trying to assign each column a value of the array. Here is an example.
pg_insert = ['12/09/2015', 41, 'test account', '41.0']
Table.create([date: pg_insert[0],
account_number: pg_insert[1],
account_name: pg_insert[2],
values: pg_insert[3]])
Is there a way where I can loop this so I can put i in pg_insert instead of having to type out numbers? I'm not sure how to loop inside of the create() parameter. Is there any way around this?
Any suggestions would be great thanks.
Table.create is accepting a Hash, I'm sure.
So here is what you can do:
Make an Array called keys that contains 4 symbols :date, :account_number, :account_name, and :values.
pg_insert is already an Array.
Now you can put the two Arrays together to make the Hash you need: Hash[keys.zip(pg_insert)]
This allows you to call Table.create like this: Table.create(Hash[keys.zip(pg_insert)])
Here is the finished code then:
keys = [:date, :account_number, :account_name, :values]
pg_insert = ['12/09/2015', 41, 'test account', '41.0']
Table.create(Hash[keys.zip(pg_insert)]) # or Table.create Hash[keys.zip(pg_insert)] if you don't want so many parentheses.
Note that pg_insert will always have to be in the same order as keys.
You can read more about Array#zip and Hash.new to understand how those work. This SO link might also be helpful: Converting an array of keys and an array of values into a hash in Ruby
I have a Hash
person_params = {"firstname"=>"",
"lastname"=>"tom123",
"addresses_attributes"=>
{"0"=>
{"address_type"=>"main",
"catalog_delivery"=>"0",
"street"=>"tomstr",
"city"=>"tomcity"
}
}
}
With person_params[:addresses_attributes], I get:
# => {"0"=>{"address_type"=>"main", "catalog_delivery"=>"0", "street"=>"tomstr", "zip"=>"", "lockbox"=>"", "city"=>"tomcity", "country"=>""}}
1) How can I get a new hash without the leading 0?
desired_hash = {"address_type"=>"main", "catalog_delivery"=>"0", "street"=>"tomstr", "zip"=>"", "lockbox"=>"", "city"=>"tomcity", "country"=>""}
2) How can I check whether the attributes in the new hash are empty?
Answer 1:
person_params[:addresses_attributes]['0']
Answer 2:
hash = person_params[:addresses_attributes]['0']
hash.empty?
This looks just like a params hash from Rails =D. Anyway, it seems that your addresses_attributes contains some nested attributes. This means that what you have in practice is more of an array of hashes than a single hash, and that's what you see right? Instead of it being an actually Ruby Array, it is a hash with the index as a string.
So how do you get the address attributes? Well if you only want to get the first address, here are some ways to do that:
person_params[:addresses_attributes].values.first
# OR
person_params[:addresses_attributes]["0"]
In the first case, we will just take the values from the addreses_attributes hash, which gives us an Array from which we can take the first item. If there are no values in addresses_attributes, then we will get nil.
In the second case, we will just ask for the hash value with the key "0". If there are no values in addresses_attributes, we will get nil with this method also. (You might want to avoid using the second case, if you are not confident that the addresses_attributes hash will always be indexed from "0" and incremented by "1")
I have the following array:
arr = [["Example"]]
I need to reduce it to just "Example" (basically, just remove the array).
I know I could do arr[0][0], but am curious if there's a simple method to just remove the string from the array without using indexes.
For clarification...there will only ever be a single item in the array.
For a single item, you can use:
[['array']].join
=> 'array'
Updated with more examples
If you have multiple items, the strings will be combined:
[['array'], ['array']].join
=> 'arrayarray'
And if you pass a parameter to the join method:
[['array'], ['array']].join('&')
=> 'array&array'
While this is not as efficient as [0][0], it will still work:
arr.flatten.first
I am iterating on a array within a Object van. I am trying to pop the elements of the array into another object array. See below.
#van.bikes.each { #garage<<( #van.removebike )}
def removebike
#bikes.pop
end
When I do this the resulting array in the garage has missing elements and/or duplicate elements.
The reason for this is that when ruby iterates on the array it sets number of iterations based on the original array size. When you pop an element from that array the size changes so the iteration can not work properly.
You can use instead,
#van.bikes.count.times { #garage<<( #van.removebike )}
You can try this too..
#garage = []
#van.bikes.each{|bike| #garage << bike}