Get Index of String Scan Results in Ruby

Get index of string scan results in ruby

Try this:

res = []
"abab".scan(/a/) do |c|
  res << [c, $~.offset(0)[0]]
end

res.inspect # => [["a", 0], ["a", 2]]

Get the index of all characters in ruby

Use Enumerator#with_index:

str = "sssaadd"
str.each_char.with_index do |char, index|
  puts "#{index}: #{char}"
end

How do I find the index of a character in a string in Ruby?

index(substring [, offset]) → fixnum or nil
index(regexp [, offset]) → fixnum or nil

Returns the index of the first occurrence of the given substring or pattern (regexp) in str. Returns nil if not found. If the second parameter is present, it specifies the position in the string to begin the search.

"hello".index('e')             #=> 1
"hello".index('lo')            #=> 3
"hello".index('a')             #=> nil
"hello".index(?e)              #=> 1
"hello".index(/[aeiou]/, -3)   #=> 4

Check out ruby documents for more information.

Return index of all occurrences of a character in a string in ruby

s = "a#asg#sdfg#d##"
a = (0 ... s.length).find_all { |i| s[i,1] == '#' }

View results of a search in index

With this code, i finally achieved what I was trying to do.

<div class="container">
  <div class="row">
    <% if params[:term].present? %>
      <% if @products_search.present? %>
        <% @products_search.each do |product| %>
        <div class="col-sm-8 col-sm-offset-2">
          <%= product.name %><br>
          <%= product.description %><br>
          <%= humanized_money_with_symbol(product.price)%><br>
          <%= link_to "Show Product", product_path(product) %>
        </div>
        <%end%>
      <% else %>
        <h1>No products found!</h1>
      <%end%>
    <% else %>
      <% @products.each do |product| %>
      <div class="col-sm-8 col-sm-offset-2">
        <%= product.name %><br>
        <%= product.description %><br>
        <%= humanized_money_with_symbol(product.price)%><br>
        <%= link_to "Show Product", product_path(product) %>
      </div>
      <%end%>
      <%end%>
  </div>
</div>

How to get index with multiple values but return single result

after further researching, the code below works :

diff = []

actual[row_num].join(",").scan(actual[row_num][col_num]) do |c|

  diff << [c, Regexp.last_match.offset(0).first]   

end

I applied this on the logic of my code. I first converted the Array to String using JOIN including Commas. And scan each ROW & COLUMN.

I then call each result as diff.last[1], to get the exact INDEX.

Hopefully this helps someone the same as my problem.

Find indices of elements that match a given condition

Ruby 1.9:

arr = ['x', 'o', 'x', '.', '.', 'o', 'x']
p arr.each_index.select{|i| arr[i] == 'x'} # =>[0, 2, 6]

Code

ruby regex: match and get position(s) of

Using Ruby 1.8.6+, you can do this:

require 'enumerator' #Only for 1.8.6, newer versions should not need this.

s = "AustinTexasDallasTexas"
positions = s.enum_for(:scan, /Texas/).map { Regexp.last_match.begin(0) }

This will create an array with:

=> [6, 17]

In Ruby, how do I find the index of an element in an array in a case-insensitive way?

Use Array#find_index:

a = ["A", "B", "C"]
a.find_index {|item| item.casecmp("b") == 0 }
# or
a.find_index {|item| item.downcase == "b" }

Note that the usual Ruby caveats apply for case conversion and comparison of accented and other non-Latin characters. This will change in Ruby 2.4. See this SO question: Ruby 1.9: how can I properly upcase & downcase multibyte strings?

In Ruby how do I find the index of one of an array of elements?

find_index takes a single element. You could find the minimum by doing something like

a = ["a", "b", "c"]
to_find = ["b", "c"]
to_find.map {|i| a.find_index(i) } .compact.min # => 1

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