Find value in an array

Question

In Ruby  how can I find a value in an array

User · Answer

Like this   a      a    b    c    d    e    a 2     a 0    a 1        gt   cab  a 6                       gt  nil a 1  2                    gt     b    c    a 1  3                    gt     b    c    d    a 4  7                    gt     e    a 6  10                   gt  nil a -3  3                   gt     c    d    e      special cases a 5                       gt  nil a 5  1                    gt     a 5  10                   gt       or like this   a      a    b    c    a index  b        gt  1 a index  z        gt  nil   See the manual

User · Answer

Using Array select will give you an array of elements that meet the criteria  But if you re looking for a way of getting the element out of the array that meets your criteria  Enumerable detect would be a better way to go   array    1 2 3  found   array select   e  e    3     gt   3  found   array detect   e  e    3     gt  3   Otherwise you d have to do something awkward like   found   array select   e  e    3  first

User · Answer

I know this question has already been answered  but I came here looking for a way to filter elements in an Array based on some criteria  So here is my solution example  using select  I find all constants in Class that start with  RUBY    Class constants select   c  c to s      RUBY       UPDATE  In the meantime I have discovered that Array grep works much better  For the above example    Class constants grep   RUBY     did the trick

User · Answer

I m guessing that you re trying to find if a certain value exists inside the array  and if that s the case  you can use Array include  value    a    1 2 3 4 5  a include  3        gt  true a include  9        gt  false   If you mean something else  check the Ruby Array API

User · Answer

This answer is for everyone that realizes the accepted answer does not address the question as it currently written   The question asks how to find a value in an array  The accepted answer shows how to check whether a value exists in an array   There is already an example using index  so I am providing an example using the select method   1 9 3-p327  012  gt  x    1 2 3 4 5      gt   1  2  3  4  5   1 9 3-p327  013  gt  x select   y  y    1      gt   1

User · Answer

Thanks for replies   I did like this   puts  find  if array include  value

User · Answer

you can use Array select or Array index to do that

User · Answer

If you want find one value from array  use Array find  arr    1 2 6 4 9   arr find   e  e   3    0       gt   6  See also  arr select   e  e   3    0     gt    6  9   e include  6                 gt  true  To find if a value exists in an Array you can also use  in  when using ActiveSupport   in  works for any object that responds to  include   arr    1  6  6 in  arr                    gt  true

User · Answer

You can go for array methods   To see all array methods use methods function with array  For Example   a     name    surname    a methods   By the way you can use different method for checking value in array You can use a include   name

User · Answer

Use   myarray index  valuetoFind   That will return you the index of the element you want or nil if your array doesn t contain the value

[ruby] Find value in an array

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