irb | 易学教程

How can I reload a script in IRB?

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问题 I am writing a Ruby script for use in the Rails environment, but I chose to run it from irb because reloading the Rails console can be a pain. Now the wait time is much shorter from irb, but I'm bothered that I have to restart irb and require the script everytime I make a change. Is there a simpler way of reloading a script from irb? I found a method in this thread, but that only applies to gem files apparently. My require statement looks like this require "#{File.expand_path(__FILE__)}/..

rbenv irb history is not saving

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I install ruby via rbenv-installer . When I use irb console, I can use history by pressing up and down on keyboard. And when I exited from console and start it again, I can't use prewious history. When I press up-arrow-button, nothing was happened. When I used rvm this option was working. How can I switch on it in rbenv? arturtr I found this way for solving my problem. In file ~/.irbrc write: require 'irb/ext/save-history' #History configuration IRB.conf[:SAVE_HISTORY] = 100 IRB.conf[:HISTORY_FILE] = "#{ENV['HOME']}/.irb-save-history" Found in this question: irb history not working Create ~/

How to suppress the output of return value in IRB/Rails Console?

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问题 An example is if I go into IRB and do the following: jruby-1.6.7 :026 > puts [1,2,3,4,5] 1 2 3 4 5 => nil Is there anyway to suppress the nil ? The problem is if I put in a large data structure, it spams something an other irrelevant return respond. I'm more interested in seeing output from debug statements I run through a block and have to continually scroll up and look for the real data. 回答1: If you just want to suppress long output once in a while, use ;0 , like: a = [*1..10000];0 # => 0

How do I drop to the IRB prompt from a running script?

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问题 Can I drop to an IRB prompt from a running Ruby script? I want to run a script, but then have it give me an IRB prompt at a point in the program with the current state of the program, but not just by running rdebug and having a breakpoint. 回答1: you can use ruby-debug to get access to irb require 'rubygems' require 'ruby-debug' x = 23 puts "welcome" debugger puts "end" when program reaches debugger you will get access to irb. 回答2: Pry (an IRB alternative) also lets you do this, in fact it was

A JSON text must at least contain two octets

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问题 I received this error, and I couldn't find any reasonable answer to this question, so I thought I'd write a summary of the problem. If you run this snippet in irb: JSON.parse( nil ) You'll see the following error: TypeError: can't convert nil into String I was kind of expecting the function to return nil , and not a TypeError . If you convert all input using to_s , then you'll see the octet error: JSON::ParserError: A JSON text must at least contain two octets! That's just fine and well. If

Ruby: How to make IRB print structure for Arrays and Hashes

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When I make a new array/hash in irb , it prints out a nice format to show the structure, ex. ["value1", "value2", "value3"] {"key1" => "value1"} ... but when I try to print out my variables using puts , I get them collapsed: value1 value2 value3 key1 value1 I gather that puts is not the right command for what I want, but what is? I want to be able to view my variables in irb in the first format, not the second. You can either use the inspect method: a=["value1", "value2", "value3"] puts a.inspect Or, even better, use the pp (pretty print) lib: require 'pp' a=["value1", "value2", "value3"] pp a

How to suppress Rails console/irb outputs

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I'm stuck with a pretty weird problem. I was testing some db entries in our production server in Rails Console where almost all the commands were resulting a huge number of o/p lines, due to which the ssh channel was getting hanged :( Is there a way to suppress the console/irb screenfuls? Thanks You can append ; nil to all your your commands/statements. Example: users = User.all; nil Actually irb prints the (return) value of the last executed statement. Thus in this case it'll print only nil as nil is the last executed valid statement :) LarsDK In search of a solution how to silence the irb

How do you list the currently available objects in the current scope in ruby?

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问题 I'm new to ruby and I'm playing around with the IRB. I found that I can list methods of an object using the ".methods" method, and that self.methods sort of give me what I want (similar to Python's dir( builtins )?), but how can I find the methods of a library/module I've loaded via include and require? irb(main):036:0* self.methods => ["irb_pop_binding", "inspect", "taguri", "irb_chws", "clone", "irb_pushws", "public_methods", "taguri=", "irb_pwws", "public", "display", "irb_require", "irb

How to run a .rb file from IRB?

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I am starting out with Ruby on Rails. I am currently going through a tutorial where it says that I have to run a .rb file from IRB and that that will create a .xml file in my current directory. My question is how do I run a .rb file in IRB? And do I have to be in the directory where this .rb file lives when I run it in IRB? I tried the following: just typing irb on the command line in the directory of the file. That starts an IRB session as far as I understand. Then I typed irb "filename.rb" which went through but didn't create anything in the current directory but at least it didn't give any

How to get nice formatting in the Rails console

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I want to get something like this to look nice: >> ProductColor.all => [#<ProductColor id: 1, name: "White", internal_name: "White", created_at: "2009-06-10 04:02:44", updated_at: "2009-06-10 04:02:44">, #<ProductColor id: 2, name: "Ivory", internal_name: "Ivory", created_at: "2009-06-10 04:02:44", updated_at: "2009-06-10 04:02:44">, #<ProductColor id: 3, name: "Blue", internal_name: "Light Blue", created_at: "2009-06-10 04:02:44", updated_at: "2009-06-10 04:02:44">, #<ProductColor id: 4, name: "Green", internal_name: "Green", created_at: "2009-06-10 04:02:44", updated_at: "2009-06-10 04:02:44