NoMethodError error for String#[]=

[razum2um]

https://ruby-doc.org/core-2.5.1/String.html#method-i-5B-5D-3D

say = "I love Ruby"
say['love'] = "*love*"
say

expected

I *love* Ruby

actual

NoMethodError: undefined method `[]=' for "I love Ruby"

this chunk of code is notably shown on ruby homepage

[easydatawarehousing]

Thanks for reporting this issue. But this is something I don't think I can change. TryRuby uses Opal for running Ruby in a web browser. Opal transpiles ruby to javascript. In javascript strings are immutable. Opal copies this behavior, see undocumented features.

I am in the process of updating the Opal version used by TryRuby. Using the latest Opal (0.11.4) the string indexing does work.

say = "I love Ruby"
say['love']

it returns 'love' as expected.

Starting irb with immutable strings (RUBYOPT=--enable-frozen-string-literal irb) and using your example will produce a similar error on the []= method.