I have this data in a hash:
[{"total_time"=>"00:04:48.563044"}, {"total_time"=>"00:05:29.835918"}, {"total_time"=>"00:09:38.622569"}]
But I want this:
["00:04:48.563044", "00:05:29.835918", "00:09:38.622569"]
Needs to work with Ruby 1.8.7.
You might manage with this:
list.collect(&:values).flatten
There's a ton of ways to accomplish this. Let's break it down into the basic steps you need to accomplish:
Iterate over each item in the array of hashes
For each item, grab the time value
Reassemble those into a list
Since you want to grab the result for each item, not just look at it, you'll want to use map (or collect, they're actuality the same method). That will take care of steps 1 and 3. And step 2, by itself, is pretty easy. You just need to get the value for a key with item['total_time']. Put it all together, and you've got this:
times.map{ |time| time['total_time'] }
Speaking about a ton of ways to accomplish this:
a = [{"total_time"=>"00:04:48.563044"}, {"total_time"=>"00:05:29.835918"}, {"total_time"=>"00:09:38.622569"}]
p a.map(&:flatten).map(&:last)
Related
I am trying to create a data field using Mockaroo and they say they have Ruby support but I know nothing about Ruby so I am trying to find out how to do a field that will randomly choose between the 3 options.
now() or
now()+days(-1) or
now()+days(-2) or
now()+days(-3)
Idea 1
I was initially thinking something using random like now()+days(this.rand(-3))
Idea 2
I also thought of using or logic like now() or now()+days(-3) or etc...
This answer may end up being different than a typical ruby solution since Mockaroo has their own little API to use too... Appreciate any help that can be given.
Turns out I had to use the random function first and pass in min and max date parameters.
random(now()+days(2), now()+days(-3))
I am working on an untrained classifier model. I am working in Python 2.7. I have a loop. It looks like this:
features = [0 for i in xrange(len(dictionary))]
for bgrm in new_scored:
for i in xrange(len(dictionary)):
if bgrm[0] == dictionary[i]:
features[i] = int(bgrm[1])
break
I have a "dictionary" of bigrams that I have collected from a data set containing customer reviews and I would like to construct feature arrays of each review corresponding to the dictionary I have created. It would contain the frequencies of the bigrams found within the review of the features in the dictionary (I hope that makes sense). new_scored is a list of tuples which contains the bigrams found within a particular review paired with their relative frequency of occurrence in that review. The final feature arrays will be the same length as the original dictionary with few non zero entries.
The above works fine but I am looking at a data set of 13000 reviews, for each review to loop through this code is going to take for eeever (if my computer doesnt run out of RAM first). I have been sitting with it for a while and cannot see how I can condense it.
I am very new to python so I was hoping a more experienced could help with condensing it or perhaps point me in the right direction towards a library that will contain the function I need.
Thank you in advance!
Consider making dictionary an actual dict object (or some fancier subclass of dict if it better suits your needs), as opposed to an iterable (list or tuple seems like what it is now). dictionary could map bigrams as keys to an integer identifier that would identify a feature position.
If you refactor dictionary that way, then the loop can be rewritten as:
features = [0 for key in dictionary]
for bgram in new_scored:
try:
features[dictionary[bgram[0]]] = int(bgrm[1])
except KeyError:
# do something if the bigram is not in the dictionary for some reason
This should convert what was an O(n) traversal through dictionary into a hash lookup.
Hope this helps.
I have been playing around with the projects on learnstreet but I sort of noticed something intresting about the way that they access elements in an array and was hoping to get some clarification.
To access the first element in an array, I know that I can do something like
a = [2,4,5,6,7]
a[0]
output=> 2
However on the learnstreet site they access the first element by doing something like
a = [2,4,5,6,7]
a[0,1]
output => 2
My speculations might be that they are using an older version of ruby that requires that you that. Correct me if I am wrong, am just curious to why it was done that way.
Actually to verify this, I went a step further and tried it in pry but I noticed that using their approach only returned the first element of the array.
My version of ruby is => ruby 1.9.3p327 (2012-11-10 revision 37606) [x86_64-darwin12.2.0]
That is just another way of grabbing the first index saying:
a[0, 1]
Start at the 0 index and grab a slice of length one. This is useful for grabbing a "chunk" or "slice" of the array. Typically, when only involving a certain item of the array, it is clearer to use the single index version. Namely a[0].
See here for more clarification.
The best of grabbing the n number of index values
a[0..1]
It will return 0 index to index 1
eg:- a = [2,4,5,6,7]
a[0..1]
output => [2,4]
It will be neat and clean but it will return the value in array not in string.
I have a list of adjectives (found here), that I would like to be the basis for a "random_adjective(category)" method.
I'm really just taking a stab at this, as my first real attempt at a useful program.
Step 1: Open file, remove formatting. No problem.
list=File.read('adjectivelist')
list.gsub(/\n/, " ")
The next step is to break the string up by category..
list.split(" ")
Now I have an array of every word in the file. Neat. The ones with a tilde before them represent the category names.
Now I would like to break up this LARGE array into several smaller ones, based on category.
I need help with the syntax here, although the pseudocode for this would be something like
Scan the array for an element which begins with a tilde.
Now create a new array based on the name of that element sans the tilde, and ALSO place this "category name" into the "categories" array. Now pull all the elements from the main array, and pop them into the sub-array, until you meet another tilde. Then repeat the process until there are no more elements in the array.
Finally I would pull a random word from the category named in the parameter. If there was no category name matching the parameter, it would return false and exit (this is simply in case I want to add more categories later.)
Tips would be appreciated
You may want to go back and split first time around like this:
categories = list.split(" ~")
Then each list item will start with the category name. This will save you having to go back through your data structure as you suggest. Consider that a tip: sometimes it's better to re-think the start of a coding problem than to head inexorably forwards
The structure you are reaching towards is probably a Hash, where the keys are category names, and the values are arrays of all the matching adjectives. It might look like this:
{
'category' => [ 'word1', 'word2', 'word3' ]
}
So you might do this:
words_in_category = Hash.new
categories.each do |category_string|
cat_name, *words = category_string.split(" ")
words_in_category[cat_name] = words
end
Finally, to pick a random element from an array, Ruby provides a very useful method sample, so you can just do this
words_in_category[ chosen_category ].sample
. . . assuming chosen_category contains the string name of an actual category. I'll leave it to you to figure out how to put this all together and handle errors, bad input etc
Use slice_before:
categories = list.split(" ").slice_before(/~\w+/)
This will create an sub array for each word starting with ~, containing all words before the next matching word.
If this file format is your original and you have freedom to change it, then I recommend you save the data as yaml or json format and read it when needed. There are libraries to do this. That is all. No worry about the mess. Don't spend time reinventing the wheel.
Still new to Ruby - I apologize in advance if this has been asked.
I am using HTTParty to get data from an API, and it is returning an array of JSON data that I can't quite figure out how to parse.
#<Net::HTTPOK:0x1017fb8c0>
{"ERRORARRAY":[],"DATA":[{"ALERT":1,"LABEL":"hello","WATCHDOG":1},{"LABEL":"goodbye","WATCHDOG":1}
I guess the first question is that I don't really know what I am looking at. When I do response.class I get HTTParty::Response. It appears to be a Hash inside an array? I am not sure. Anyway, I want a way to just grab the "LABEL" for every separate array, so the result would be "hello", "goodbye". How would I go about doing so?
you don't need to parse it per say. what you could do is replace ':' with '=>' and evaluate it.
example: say you have ["one":"a","two":"b"], you could set s to equal that string and do eval s.gsub(/^\[/, '{').gsub(/\]$/, '}').gsub('":', '"=>') will yield a ruby hash (with inspect showing {"one"=>"a", "two"=>"b"})
alternatively, you could do something like this
require 'json'
string_to_parse = "{\"one\":\"a\",\"two\":\"b\"}"
parsed_and_a_hash = JSON.parse(string_to_parse)
parsed_and_a_hash is a hash!
If that's JSON, then your best bet is to install a library that handles the JSON format. There's really no point in reinventing the wheel (although it is fun). Have a look at this article.
If you know that the JSON data will always, always be in exactly the same format, then you might manage something relatively simple without a JSON gem. But I'm not sure that it's worth the hassle.
If you're struggling with the json gem, consider using the Crack gem. It has the added benefit of also parsing xml.
require 'crack'
my_hash_array = Crack::JSON.parse(my_json_string)
my_hash_array = Crack::XML.parse(my_xml_string)