Ruby

Really sorry that I have to say I don't understand this report at all. Please tell us about your problem a bit more in detail.

shyouhei (Shyouhei Urabe) wrote:

Really sorry that I have to say I don't understand this report at all. Please tell us about your problem a bit more in detail.

the replacement doesn't happen

try in python and see the diff

a = "test ?" b = "?" c = "\\&" a.replace(b,c) 

@thiaguerd I don't understand - the String#replace method only takes one argument - you're calling it with two so that's not going to work for a start. Secondly, the method doesn't replace occurrences of one string with another, which is what I think you think it does. It replaces the whole string with another string.

https://ruby-doc.org/core-2.6.3/String.html#method-i-replace

So your code doesn't work because that's just not what this method does or is documented to do in Ruby.

include ERB::Util def r puts "Enter original" a = gets.chomp puts "Enter a pattern to replace" b = gets.chomp puts "Enter a replacement" c = gets.chomp puts "a: #{a}" puts "b: #{b}" puts "c: #{c}" c = html_escape c puts "c escaped: #{c}" puts "final: #{a.gsub(b,c)}" end 

running

>> r Enter original my text and my source: ### Enter a pattern to replace ### Enter a replacement xml.scan(/\<tag>[\s\S]*?\<\/tag\>/) a: my text and my source: ### b: ### c: xml.scan(/\<tag>[\s\S]*?\<\/tag\>/) c escaped: xml.scan(/\&lt;tag&gt;[\s\S]*?\&lt;\/tag\&gt;/) final: my text and my source: xml.scan(/###lt;tag&gt;[\s\S]*?###lt;\/tag###gt;/) => nil >> # should not be: "final: my text and my source: xml.scan(/\&lt;tag&gt;[\s\S]*?\&lt;\/tag\&gt;/)" ?? 

on Python 3.7.1¶

import html def r(): a = input('Enter original:') b = input('Enter a pattern to replace:') c = input('Enter a replacement:') print(f"a: {a}") print(f"b: {b}") print(f"c: {c}") c = html.escape(c) print(f"c escaped: {c}") print(f"final: {a.replace(b,c)}") 

running

>>> r() Enter original:my text and my source: ### Enter a pattern to replace:### Enter a replacement:xml.scan(/\<tag>[\s\S]*?\<\/tag\>/) a: my text and my source: ### b: ### c: xml.scan(/\<tag>[\s\S]*?\<\/tag\>/) c escaped: xml.scan(/\&lt;tag&gt;[\s\S]*?\&lt;\/tag\&gt;/) final: my text and my source: xml.scan(/\&lt;tag&gt;[\s\S]*?\&lt;\/tag\&gt;/) >>> # here works ... 

gsub(pattern, replacement) always interprets replacement as a regex replacement directive.
You can use the block form to substitute verbatim:

a = "test ?" b = "?" c = "\\&" a.gsub(b) { c } #=> "test \\&"