Chaining in rails (ERB) files

Question

What is rubys (ERB) equivalent of the following PHP code?

<?php echo $first_variable . " " . $second_variable ?>

score 3 · Answer 1 · edited May 23 '17 at 11:52

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<%= "#{first_variable} #{second_variable}" %>

Note that variables gonna be transformed to string representation (which could produce some unexpected outputs like "Photo:0x0000000dc9f5b0"). More on various ways to concatenate strings here: String concatenation in Ruby

edited May 23 '17 at 11:52

Community

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answered Jun 07 '15 at 16:37

twonegatives

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score 0 · Accepted Answer · edited Jun 08 '15 at 08:40

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You can do it like this:
<%= first_variable_value + " " + second_variable_value %>

However, if variables store Fixnum instead of String then the following error occurs
TypeError: String can't be coerced into Fixnum.

Therefore the best approach would be
<%= "#{first_variable} #{last_variable}" %>

Interpolation implecitly converts the Fixnum into String and problem solved.

edited Jun 08 '15 at 08:40

Shiva

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answered Jun 07 '15 at 16:29

sansarp

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That's exactly I was looking for! Thank you :) – Jakub Kohout Jun 07 '15 at 16:36
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I think you meant `<%= first_variable_value + " " + second_variable_value %>`. The way you have it, it will just print the words `first_variable_value` and `second_variable_value` – Jim Deville Jun 07 '15 at 16:40
in case `first_variable` is a complex object (e.g. Rails model instance), this would end with `undefined method + for Model:0x0000000dd7ef30` – twonegatives Jun 08 '15 at 07:13

Arslan Ali · Answer 3 · 2015-06-07T17:37:37.223

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You don't need " to print a variable; you can do so without ".

<%= first_variable %>

This is equivalent of following PHP code:

<?php echo $first_variable ?>

So in order to do what you have asked in your question, the following code is suitable:

<%= first_variable + " " + last_variable %>

You don't need to surround your variables with ". And + operator here does the job for concatenation.

And in case, if you are not sure that variables are actually string object, the you can use either of the following techniques:

<%= first_variable.to_s + " " + last_variable.to_s %>
<%= "#{first_variable} #{last_variable}" %>

edited Jun 07 '15 at 17:37

answered Jun 07 '15 at 17:19

Arslan Ali

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not really true. in case `first_variable` is a complex object (e.g. Rails model instance), this would end with `undefined method + for Model:0x0000000dd7ef30` – twonegatives Jun 07 '15 at 17:33
I've assumed them to be strings. Let me edit the answer. – Arslan Ali Jun 07 '15 at 17:36

Chaining in rails (ERB) files

3 Answers3