(See edit at the bottom of this post)
I'm making a program in Elixir that counts the types of HTML tags from a list of tags that I've already obtained. This means that the key should be the tag and the value should be the count.
e.g. in the following sample file
<html><head><body><sometag><sometag><sometag2><sometag>
My output should be something like the following:
html: 1
head: 1
body: 1
sometag: 3
sometag2: 1
Here is my code:
def tags(page) do
taglist = Regex.scan(~r/<[a-zA-Z0-9]+/, page)
dict = Map.new()
Enum.map(taglist, fn(x) ->
tag = String.to_atom(hd(x))
Map.put_new(dict, tag, 1)
end)
end
I know I should be probably using Enum.each instead but when I do that my dictionary ends up just being empty instead of incorrect.
With Enum.map, this is the output I receive:
iex(15)> A3.test
[%{"<html" => 1}, %{"<body" => 1}, %{"<p" => 1}, %{"<a" => 1}, %{"<p" => 1},
%{"<a" => 1}, %{"<p" => 1}, %{"<a" => 1}, %{"<p" => 1}, %{"<a" => 1}]
As you can see, there are duplicate entries and it's turned into a list of dictionaries. For now I'm not even trying to get the count working, so long as the dictionary doesn't duplicate entries (which is why the value is always just "1").
Thanks for any help.
EDIT: ------------------
Okay so I figured out that I need to use Enum.reduce
The following code produces the output I'm looking for (for now):
def tags(page) do
rawTagList = Regex.scan(~r/<[a-zA-Z0-9]+/, page)
tagList = Enum.map(rawTagList, fn(tag) -> String.to_atom(hd(tag)) end)
Enum.reduce(tagList, %{}, fn(tag, acc) ->
Map.put_new(acc, tag, 1)
end)
end
Output:
%{"<a": 1, "<body": 1, "<html": 1, "<p": 1}
Now I have to complete the challenge of actually counting the tags as I go...If anyone can offer any insight on that I'd be grateful!
First of all, it is not the best idea to parse html with regexes. See this question for more details (especially the accepted answer).
Secondly, you are trying to write imperative code in functional language (this is about first version of your code). Variables in Elixir are immutable. dict will always be an empty map. Enum.map takes a list and always returns new list of the same length with all elements transformed. Your transformation function takes an empty map and puts one key-value pair into it.
As a result you get a list with one element maps. The line:
Map.put_new(dict, tag, 1)
doesn't update dict in place, but creates new one using old one, which is empty. In your example it is exactly the same as:
%{tag => 1}
You have couple of options to do it differently. Closest approach would be to use Enum.reduce. It takes a list, an initial accumulator and a function elem, acc -> new_acc.
taglist
|> Enum.reduce(%{}, fn(tag, acc) -> Map.update(acc, tag, 1, &(&1 + 1)) end)
It looks a little bit complicated, because there are couple of nice syntactic sugars. taglist |> Enum.reduce(%{}, fun) is the same as Enum.reduce(taglist, %{}, fun). &(&1 + 1) is shorthand for fn(counter) -> counter + 1 end.
Map.update takes four arguments: a map to update, key to update, initial value if key doesn't exist and a function that does something with the key if it exists.
So, those two lines of code do this:
iterate over list Enum.reduce
starting with empty map %{}
take current element and map fn(tag, acc) and either:
if key doesn't exist insert 1
if it exists increment it by one &(&1 + 1)
Related
Rails 5 now support native JSON data type in MySQL, so if I have a column data that contains an array: ["a", "b", "c"], and I want to search if this column contains values, so basically I would like to have something like: data_json_cont: ["b"]. So can this query be built using ransack ?
Well I found quite some way to do this with Arrays(not sure about json contains for hash in mysq). First include this code in your active record model:
self.columns.select{|column| column.type == :json}.each do |column|
ransacker "#{column.name}_json_contains".to_sym,
args: [:parent, :ransacker_args] do |parent, args|
query_parts = args.map do |val|
"JSON_CONTAINS(#{column.name}, '#{val.to_json}')"
end
query = query_parts.join(" * ")
Arel.sql(query)
end
end
Then assuming you have class Shirt with column size, then you can do the following:
search = Shirt.ransack(
c: [{
a: {
'0' => {
name: 'size_json_contains',
ransacker_args: ["L", "XL"]
}
},
p: 'eq',
v: [1]
}]
)
search.result
It works as follows: It checks that the array stored in the json column contains all elements of the asked array, by getting the result of each json contains alone, then multiplying them all, and comparing them to arel predicate eq with 1 :) You can do the same with OR, by using bitwise OR instead of multiplication.
I have a CSV file with data like:
ID,Name,Role,Project
1,James,Owner,TST
2,Ed,Assistant,TST
3,Jack,Manager,TST
and want to create people whose relationships to the project are therein specified. I attempted to do it like this:
load csv from 'file:/../x.csv' as line
match (p:Project {code: line[3]})
create (n:Individual {name: line[1]})-[r:line[2]]->(p);
but it barfs with:
Invalid input '[': expected an identifier character, whitespace, '|',
a length specification, a property map or ']' (line 1, column 159
(offset: 158))
as it can't seem to dereference line in the relationship creation. if I hard-code that it works:
load csv from 'file:/../x.csv' as line
match (p:Project {code: line[3]})
create (n:Individual {name: line[1]})-[r:WORKSFOR]->(p);
so how do I make the reference?
Right now you can't as this is structural information.
Either use neo4j-import tool for that.
Or specify it manually as you did, or use this workaround:
load csv with headers from 'file:/../x.csv' as line
match (p:Project {code: line.Project})
create (n:Individual {name: lineName})
foreach (x in case line.Role when "Owner" then [1] else [] end |
create (n)-[r:Owner]->(p)
)
foreach (x in case line.Role when "Assistant" then [1] else [] end |
create (n)-[Assistant]->(p)
)
foreach (x in case line.Role when "Manager" then [1] else [] end |
create (n)-[r:Manager]->(p)
)
Michael's answer stands, however, I've found that what I can do is specify an attribute to the relationship, like this:
load csv from 'file:/.../x.csv' as line
match (p:Project {code: line[3]})
create (i:Individual {name: line[1]})-[r:Role { type: line[2] }]->(p)
and I can make Neo4j display the type attribute of the relationship instead of the label
this question is old, but there is a post by Mark Needham
that provide a great and easy solution using APOC
as follow
load csv with headers from "file:///people.csv" AS row
MERGE (p1:Person {name: row.node1})
MERGE (p2:Person {name: row.node2})
WITH p1, p2, row
CALL apoc.create.relationship(p1, row.relationship, {}, p2) YIELD rel
RETURN rel
note: the "YIELD rel" is essential and so for the return part
I am building a CSV file parser through node and Angular . so basically a user upload a csv file , on my server side which is node the csv file is traversed and parsed using node-csv
. This works fine and it returns me an array of object based on csv file given as input , Now on angular end I need to display two table one is csv file data itself and another is cross tabulation analysis. I am facing problem while rendering data, so for a table like
I am getting parse responce as
For cross tabulation we need data in a tabular form as
I have a object array which I need to manipulate in best possible way so as to make easily render on html page . I am not getting a way how to do calculation on data I get so as to store cross tabulation result .Any idea on how should I approach .
data json is :
[{"Sample #":"1","Gender":"Female","Handedness;":"Right-handed;"},{"Sample #":"2","Gender":"Male","Handedness;":"Left-handed;"},{"Sample #":"3","Gender":"Female","Handedness;":"Right-handed;"},{"Sample #":"4","Gender":"Male","Handedness;":"Right-handed;"},{"Sample #":"5","Gender":"Male","Handedness;":"Left-handed;"},{"Sample #":"6","Gender":"Male","Handedness;":"Right-handed;"},{"Sample #":"7","Gender":"Female","Handedness;":"Right-handed;"},{"Sample #":"8","Gender":"Female","Handedness;":"Left-handed;"},{"Sample #":"9","Gender":"Male","Handedness;":"Right-handed;"},{"Sample #":";"}
There are many ways you can do this and since you have not been very specific on the usage, I will go with the simplest one.
Assuming you have an object structure such as this:
[
{gender: 'female', handdness: 'lefthanded', id: 1},
{gender: 'male', handdness: 'lefthanded', id: 2},
{gender: 'female', handdness: 'righthanded', id: 3},
{gender: 'female', handdness: 'lefthanded', id: 4},
{gender: 'female', handdness: 'righthanded', id: 5}
]
and in your controller you have exposed this with something like:
$scope.members = [the above array of objects];
and you want to display the total of female members of this object, you could filter this in your html
{{(members | filter:{gender:'female'}).length}}
Now, if you are going to make this a table it will obviously make some ugly and unreadable html so especially if you are going to repeat using this, it would be a good case for making a directive and repeat it anywhere, with the prerequisite of providing a scope object named tabData (or whatever you wish) in your parent scope
.directive('tabbed', function () {
return {
restrict: 'E',
template: '<table><tr><td>{{(tabData | filter:{gender:"female"}).length}}</td></tr><td>{{(tabData | filter:{handedness:"lefthanded"}).length}}</td></table>'
}
});
You would use this in your html like so:
<tabbed></tabbed>
And there are ofcourse many ways to improve this as you wish.
This is more of a general data structure/JS question than Angular related.
Functional helpers from Lo-dash come in very handy here:
_(data) // Create a chainable object from the data to execute functions with
.groupBy('Gender') // Group the data by its `Gender` attribute
// map these groups, using `mapValues` so the named `Gender` keys persist
.mapValues(function(gender) {
// Create named count objects for all handednesses
var counts = _.countBy(gender, 'Handedness');
// Calculate the total of all handednesses by summing
// all the values of this named object
counts.Total = _(counts)
.values()
.reduce(function(sum, num) { return sum + num });
// Return this named count object -- this is what each gender will map to
return counts;
}).value(); // get the value of the chain
No need to worry about for-loops or anything of the sort, and this code also works without any changes for more than two genders (even for more than two handednesses - think of the aliens and the ambidextrous). If you aren't sure exactly what's happening, it should be easy enough to pick apart the single steps and their result values of this code example.
Calculating the total row for all genders will work in a similar manner.
I've stared at this so long I'm going in circles...
I'm using the rbvmomi gem, and in Pry, when I display an object, it recurses down thru the structure showing me the nested objects - but to_json seems to "dig down" into some objects, but just dump the reference for others> Here's an example:
[24] pry(main)> g
=> [GuestNicInfo(
connected: true,
deviceConfigId: 4000,
dynamicProperty: [],
ipAddress: ["10.102.155.146"],
ipConfig: NetIpConfigInfo(
dynamicProperty: [],
ipAddress: [NetIpConfigInfoIpAddress(
dynamicProperty: [],
ipAddress: "10.102.155.146",
prefixLength: 20,
state: "preferred"
)]
),
macAddress: "00:50:56:a0:56:9d",
network: "F5_Real_VM_IPs"
)]
[25] pry(main)> g.to_json
=> "[\"#<RbVmomi::VIM::GuestNicInfo:0x000000085ecc68>\"]"
Pry apparently just uses a souped-up pp, and while "pp g" gives me close to what I want, I'm kinda steering as hard as I can toward json so that I don't need a custom parser to load up and manipulate the results.
The question is - how can I get the json module to dig down like pp does? And if the answer is "you can't" - any other suggestions for achieving the goal? I'm not married to json - if I can get the data serialized and read it back later (without writing something to parse pp output... which may already exist and I should look for it), then it's all win.
My "real" goal here is to slurp up a bunch of info from our vsphere stuff via rbvmomi so that I can do some network/vm analysis on it, which is why I'd like to get it in a nice machine-parsed format. If I'm doing something stupid here and there's an easier way to go about this - lay it on me, I'm not proud. Thank you all for your time and attention.
Update: Based on Arnie's response, I added this monkeypatch to my script:
class RbVmomi::BasicTypes::DataObject
def to_json(*args)
h = self.props
m = h.merge({ JSON.create_id => self.class.name })
m.to_json(*args)
end
end
and now my to_json recurses down nicely. I'll see about submitting this (or the def, really) to the project.
The .to_json works in a recursive manner, the default behavior is defined as:
Converts this object to a string (calling to_s), converts it to a JSON string, and returns the result. This is a fallback, if no special method to_json was defined for some object.
json library has added some implementation for some common classes (check the left hand side of this documentation), such as Array, Range, DateTime.
For an array, to_json first convert all the elements to json object, concat then together, and then add the array mark [/].
For your case, you need to define your customized to_json method for GuestNicInfo, NetIpConfigInfo and NetIpConfigInfoIpAddress. I don't know your implementation about these three classes, so I wrote a example to demonstrate how to achieve this:
require 'json'
class MyClass
attr_accessor :a, :b
def initialize(a, b)
#a = a
#b = b
end
end
data = [MyClass.new(1, "foobar")]
puts data.to_json
#=> ["#<MyClass:0x007fb6626c7260>"]
class MyClass
def to_json(*args)
{
JSON.create_id => self.class.name,
:a => a,
:b => b
}.to_json(*args)
end
end
puts data.to_json
#=> [{"json_class":"MyClass","a":1,"b":"foobar"}]
Is it possible to transpose an html table (without javascript).
I m generating a table with rails (and erb) from a list of object. So it's really easy and natural to do it when each row correspond to one object. However , I need each object to be represented as a column. I would like to have only one loop and describe each column rather than doing the same loop for every columns. (That doesn't necessarily needs to be a real table , could be a list or anything which does the trick).
update
To clarify the question. I don't want to transpose an array in ruby, but to display a html table with the row vertically. My actual table is actually using one partial per row, wich generate a list of cell (td). That can be change to a list if that help. Anyway this is HTML question not a ruby one : how to display a table with the rows vertically (rather than horizontally).
You may need something like this?
class Array
def transpose
# Check here if self is transposable (e.g. array of hashes)
b = Hash.new
self.each_index {|i| self[i].each {|j, a_ij| b[j] ||= Array.new; b[j][i] = a_ij}}
return b
end
end
a = [{:a => 1, :b => 2, :c => 3}, {:a => 4, :b => 5, :c => 6}]
a.transpose #=> {:a=>[1, 4], :b=>[2, 5], :c=>[3, 6]}
Apparently, the answer is no :-(