Difference between revisions of "Ruby/C3/for-and-each-Looping-Statements/English-timed"

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{| border=1
 
{| border=1
 
|| '''Time'''
 
|| '''Time'''
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|-
 
|-
 
|  00:01
 
|  00:01
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| Welcome to the tutorial on '''for''' and '''each Loops''' in Ruby.  
+
| Welcome to the tutorial on '''for and each Loops''' in '''Ruby'''.  
  
 
|-
 
|-
 
| 00:05
 
| 00:05
−
| In this tutorial we will learn  
+
| In this tutorial, we will learn:
  
 
|-
 
|-
 
| 00:07
 
| 00:07
−
| Meaning of the term ''' “loop” '''
+
|Meaning of the term ''' “loop” '''. The different kinds of loops in '''Ruby '''
−
 
+
−
|-
+
−
| 00:08
+
−
|The different kinds of loops in '''Ruby '''
+
  
 
|-
 
|-
 
| 00:11
 
| 00:11
−
| Usage of ''' “for” ''' loop and  
+
|Usage of ''' “for” ''' loop and  Usage of ''' “each” ''' looping construct.
−
 
+
−
|-
+
−
| 00:12
+
−
|Usage of ''' “each” ''' looping construct  
+
  
 
|-
 
|-
 
|  00:14
 
|  00:14
−
|Here we are using  
+
|Here, we are using:
  
 
|-
 
|-
 
|  00:16
 
|  00:16
−
| ''' Ubuntu''' version 12.04  
+
| ''' Ubuntu''' version '''12.04'''
  
 
|-
 
|-
 
| 00:19
 
| 00:19
−
|''' Ruby '''1.9.3  
+
|''' Ruby 1.9.3 '''
  
 
|-
 
|-
 
| 00:22
 
| 00:22
−
|To follow this tutorial, you must have ''' Internet''' Connection.   
+
|To follow this tutorial, you must have ''' Internet''' connection.   
 
    
 
    
−
 
 
|-
 
|-
 
|  00:25
 
|  00:25
 
| You must also have knowledge of '''Linux'''  commands, ''' Terminal''' and ''' Text-editor.'''
 
| You must also have knowledge of '''Linux'''  commands, ''' Terminal''' and ''' Text-editor.'''
−
 
−
 
  
 
|-
 
|-
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|-
 
|-
 
|  00:34
 
|  00:34
−
|  Now let me explain what is referred to as a ''' “loop” ''' in '''Ruby. '''
+
|  Now, let me explain what is referred to as a ''' “loop” ''' in '''Ruby. '''
  
 
|-
 
|-
 
| 00:38
 
| 00:38
−
|A '''loop''' is a command or set of commands that are executed a fixed number of times.  
+
|A '''loop''' is a '''command''' or set of commands that are executed a fixed number of times.  
  
 
|-
 
|-
 
| 00:44
 
| 00:44
−
|''' Ruby''' has the following main looping statements.  
+
| Ruby has the following main looping statements.  
  
 
|-
 
|-
 
| 00:47
 
| 00:47
−
|'''for'''
+
| '''for''', '''each ''',  ''' while''', '''until'''.
−
 
+
−
|-
+
−
| 00:48
+
−
| '''each '''
+
−
 
+
−
|-
+
−
| 00:49
+
−
|''' while'''
+
−
 
+
−
|-
+
−
|  00:49
+
−
| '''until'''
+
  
 
|-
 
|-
 
| 00:50
 
| 00:50
−
|In this tutorial we will learn how to use the '''for''' and ''' each''' looping constructs.  
+
|In this tutorial, we will learn how to use the '''for''' and ''' each''' looping constructs.  
  
 
|-
 
|-
 
| 00:55
 
| 00:55
−
| Before we begin, please create the following folders in your home directory,
+
| Before we begin, please create the following folders in your home directory-
  
 
|-
 
|-
 
| 01:02
 
| 01:02
−
| ttt,  ruby hyphen tutorial, looping hyphen statements.  
+
| '''ttt,  ruby hyphen tutorial, looping hyphen statements'''.  
  
 
|-
 
|-
 
| 01:07
 
| 01:07
−
| Please create the sub folders as mentioned there
+
| Please create the sub-folders as mentioned there.
  
 
|-
 
|-
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|-
 
|-
 
| 01:15
 
| 01:15
−
|The syntax of the ''' “for” ''' loop in ''' Ruby''' is as follows:  
+
|The syntax of the ''' “for” loop''' in Ruby is as follows:  
−
 
+
  
 
|-
 
|-
 
|  01:19
 
|  01:19
 
| ''' for “variable” in “a collection of objects” '''
 
| ''' for “variable” in “a collection of objects” '''
−
 
  
 
|-
 
|-
 
|  01:22
 
|  01:22
−
|''' ruby code '''
+
|''' ruby code ''' ''' end '''
−
 
+
−
|-
+
−
|  01:23
+
−
| ''' end '''
+
  
 
|-
 
|-
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|-
 
|-
 
|  01:28
 
|  01:28
−
| Create a new file in '''gedit''' as shown in the basic level ''' Ruby''' tutorials.
+
| Create a new file in '''gedit''' as shown in the basic level ''' Ruby tutorials'''  
  
 
|-
 
|-
 
| 01:32
 
| 01:32
−
|And name it ''' “for hyphen loop dot rb” '''
+
|and name it '''for hyphen loop dot rb '''.
−
 
+
  
 
|-
 
|-
 
| 01:36
 
| 01:36
−
|I already have a working example of the ''' “for” ''' loop.  
+
|I already have a working example of the ''' “for” loop'''.  
  
 
|-
 
|-
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|-
 
|-
 
|  01:44
 
|  01:44
−
|  I have declared a ''' “for” ''' loop in this example.  
+
|  I have declared a ''' “for” loop ''' in this example.  
  
 
|-
 
|-
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|-
 
|-
 
| 01:50
 
| 01:50
−
| We declare a variable called “i” within the ''' “for” ''' loop.  
+
| We declare a variable called “i” within the ''' “for” loop'''.  
−
 
+
  
 
|-
 
|-
 
|  01:55
 
|  01:55
−
|The variable “i” gets initialized to the first element in the set of numbers 1 to 20.  
+
|The variable “i” gets initialized to the first '''element''' in the set of numbers 1 to 20.  
  
 
|-
 
|-
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|  02:07
 
|  02:07
 
| The ''' “puts” ''' method declared within the ''' “for” ''' loop is responsible for generating the output.  
 
| The ''' “puts” ''' method declared within the ''' “for” ''' loop is responsible for generating the output.  
−
 
  
 
|-
 
|-
 
| 02:14
 
| 02:14
−
|Now open the ''' terminal''' and type  
+
|Now, open the ''' terminal''' and type:
  
 
|-
 
|-
 
|  02:17
 
|  02:17
−
| ''' ruby space  for hyphen loop dot rb ''' and see the output
+
| ''' ruby space  for hyphen loop dot rb ''' and see the output.
  
 
|-
 
|-
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|-
 
|-
 
|  02:26
 
|  02:26
−
| In this example, we declared a  ''' “for”''' loop for an inclusive range.  
+
| In this example, we declared a  ''' “for”''' loop for an '''inclusive range'''.  
  
 
|-
 
|-
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|-
 
|-
 
| 02:49
 
| 02:49
−
|Here ''' “for”''' loop is implemented for a non-inclusive range of numbers 1 to 20.  
+
|Here, ''' “for”''' loop is implemented for a '''non-inclusive range''' of numbers 1 to 20.  
  
 
|-
 
|-
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|-
 
|-
 
| 02:59
 
| 02:59
−
|The last digit does not get included when you have 3 dots between numbers.  
+
|The last number does not get included when you have 3 dots between numbers.  
  
 
|-
 
|-
 
| 03:04
 
| 03:04
−
| Now open the ''' terminal''' and type ''' ruby space for hyphen loop dot rb'''
+
| Now, open the ''' terminal''' and type: ''' ruby space for hyphen loop dot rb'''
  
 
|-
 
|-
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| 03:17
 
| 03:17
 
|The output will still be an ''' array''' of numbers but will not include the number 20.  
 
|The output will still be an ''' array''' of numbers but will not include the number 20.  
−
 
  
 
|-
 
|-
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|-
 
|-
 
| 03:27
 
| 03:27
−
|The syntax of the ''' “each”''' loop in ''' Ruby''' is as follows:  
+
|The syntax of the ''' “each”''' loop in Ruby is as follows:  
  
 
|-
 
|-
 
|  03:31
 
|  03:31
−
| ''' “a collection of objects” dot each do item '''
+
| ''' “a collection of objects” dot each''', '''do item '''
  
 
|-
 
|-
 
|  03:36
 
|  03:36
−
| ''' ruby code end'''
+
| ''' ruby code''' '''end'''
  
 
|-
 
|-
 
|  03:38
 
|  03:38
 
|Let us try to understand it with an example.  
 
|Let us try to understand it with an example.  
−
 
  
 
|-
 
|-
 
|  03:42
 
|  03:42
−
| Create a new file in '''gedit''' as shown in the basic level '''Ruby''' tutorials.
+
| Create a new file in '''gedit''' as shown in the basic level '''Ruby tutorials'''  
  
 
|-
 
|-
 
| 03:46
 
| 03:46
−
|And name it '''each hyphen loop dot rb'''
+
|and name it '''each hyphen loop dot rb'''.
  
 
|-
 
|-
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| 04:06
 
| 04:06
 
|We declare a variable called “i” within the '''each''' loop.  
 
|We declare a variable called “i” within the '''each''' loop.  
−
 
  
 
|-
 
|-
 
| 04:11
 
| 04:11
 
| The “i” variable gets initialized to the first element in the set of numbers 1 to 20.  
 
| The “i” variable gets initialized to the first element in the set of numbers 1 to 20.  
−
 
  
 
|-
 
|-
 
| 04:17
 
| 04:17
−
|The '''each''' loop declaration causes the code to iterate over each element in the set 1 to 20.  
+
|The '''each''' loop declaration causes the code to iterate over each '''element''' in the set 1 to 20.  
  
 
|-
 
|-
 
| 04:23
 
| 04:23
−
|The ''' puts''' method declared within the ''' each''' is responsible for generating the output.  
+
|The ''' puts''' method declared, within the ''' each''' loop, is responsible for generating the output.  
  
 
|-
 
|-
 
| 04:30
 
| 04:30
−
|Now open the ''' terminal''' and type ''' ruby space each hyphen loop dot rb '''
+
|Now, open the ''' terminal''' and type: ''' ruby space each hyphen loop dot rb '''
  
 
|-
 
|-
 
|  04:39
 
|  04:39
 
| and see the output.  
 
| and see the output.  
−
 
  
 
|-
 
|-
 
| 04:43
 
| 04:43
−
|The output will be an array of numbers 1 to 20.  
+
|The output will be an '''array''' of numbers 1 to 20.  
−
 
+
  
 
|-
 
|-
 
|  04:46
 
|  04:46
−
| In the above example we declared an ''' each''' loop for an inclusive range.  
+
| In the above example, we declared an ''' each''' loop for an '''inclusive range'''.  
−
 
+
  
 
|-
 
|-
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|-
 
|-
 
| 05:04
 
| 05:04
−
| Non-inclusive means it will not include the last element in the collection of objects.  
+
| '''Non-inclusive''' means it will not include the last element in the collection of objects.  
  
 
|-
 
|-
 
| 05:10
 
| 05:10
−
| Here an '''each''' loop is implemented for a non-inclusive range of numbers 1 to 20.  
+
| Here, an '''each''' loop is implemented for a non-inclusive range of numbers 1 to 20.  
−
 
+
  
 
|-
 
|-
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|-
 
|-
 
| 05:20
 
| 05:20
−
| The last digit does not get included when you have 3 dots between numbers.  
+
| The last number does not get included when you have 3 dots between numbers.  
  
 
|-
 
|-
 
| 05:25
 
| 05:25
−
|Now open the '''terminal''' and type '''ruby space each hyphen loop dot rb'''
+
|Now, open the '''terminal''' and type: '''ruby space each hyphen loop dot rb'''
  
 
|-
 
|-
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|-
 
|-
 
| 05:44
 
| 05:44
−
|How would we determine which looping construct to choose?  
+
|How would we determine which looping '''construct''' to choose?  
  
 
|-
 
|-
 
| 05:48
 
| 05:48
−
|Let us try to recall the '''for''' loop construct.  
+
|Let us try to recall the '''"for" loop construct'''.  
 
   
 
   
−
 
 
|-
 
|-
 
| 05:53
 
| 05:53
−
|In the first example, we iterated over a set of numbers from 1 to 20 using '''for'''.  
+
|In the first example, we iterated over a set of numbers from 1 to 20 using '''for''' loop.  
  
 
|-
 
|-
 
| 05:59
 
| 05:59
−
| Execute ''' ruby space for hyphen loop dot rb''' in your terminal see the output.   
+
| Execute: ''' ruby space for hyphen loop dot rb''' in your terminal, see the output.   
  
 
|-
 
|-
 
|06:08
 
|06:08
−
| Now look at the code in '''gedit.'''  
+
| Now, look at the code in '''gedit.'''  
  
 
|-
 
|-
 
| 06:11
 
| 06:11
−
|When you invoke the '''for loop''', '''Ruby''' is actually calling the '''each''' method behind the scenes.  
+
|When you invoke the '''for loop''', Ruby is actually calling the '''each''' method behind the scenes.  
  
 
|-
 
|-
 
| 06:16
 
| 06:16
−
|And calling '''each''' or '''for''' will generate the same output.  
+
|And, calling '''each''' or '''for''' will generate the same output.  
  
 
|-
 
|-
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|  06:28
 
|  06:28
 
| This brings us to the end of this Spoken Tutorial.  
 
| This brings us to the end of this Spoken Tutorial.  
−
 
  
 
|-
 
|-
 
| 06:30
 
| 06:30
 
|Let's summarize.  
 
|Let's summarize.  
−
 
  
 
|-
 
|-
 
| 06:32
 
| 06:32
−
|In this tutorial we have learnt
+
|In this tutorial, we have learnt: Usage of ''' for''' loop  
−
 
+
−
|-
+
−
|  06:33
+
−
|  Usage of ''' for''' loop  
+
 
   
 
   
 
|-
 
|-
 
| 06:35
 
| 06:35
−
|Usage of  '''each''' construct  
+
| Usage of  '''each''' construct  
  
 
|-
 
|-
 
| 06:38
 
| 06:38
−
|Reasoning behind using '''each''' instead of '''for'''  
+
| Reasoning behind using '''each''' instead of '''for'''  
  
 
|-
 
|-
 
| 06:41
 
| 06:41
−
|Examples of using the above looping constructs  
+
| Examples of using the above looping constructs.
  
 
|-
 
|-
 
| 06:45
 
| 06:45
−
| As an assignment  
+
| As an assignment-
  
 
|-
 
|-
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|-
 
|-
 
| 06:50
 
| 06:50
−
|to create an output of even numbers from a set of numbers, say 1 to 20
+
|to create an output of even numbers from a set of numbers, say 1 to 20.
−
 
+
  
 
|-
 
|-
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|-
 
|-
 
| 07:00
 
| 07:00
−
|It summarises the Spoken Tutorial project.
+
|It summarizes the Spoken Tutorial project.
  
 
|-
 
|-
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|-
 
|-
 
|  07:08
 
|  07:08
−
| The Spoken Tutorial Project Team :
+
| The Spoken Tutorial project team:
  
 
|-   
 
|-   
 
| 07:11
 
| 07:11
−
|Conducts workshops using spoken tutorials  
+
| Conducts workshops using spoken tutorials.
  
 
|-
 
|-
 
|07:14
 
|07:14
−
|Gives certificates to those who pass an online test  
+
| Gives certificates to those who pass an online test.
  
 
|-
 
|-
 
| 07:18
 
| 07:18
−
|For more details, please write to contact@spoken-tutorial.org
+
|For more details, please write to: contact@spoken-tutorial.org
  
 
|-
 
|-
 
|  07:23
 
|  07:23
−
| Spoken Tutorial Project is a part of the Talk to a Teacher project.
+
| '''Spoken Tutorial''' project is a part of the '''Talk to a Teacher''' project.
  
 
|-
 
|-
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|-
 
|-
 
| 07:33
 
| 07:33
−
|More information on this Mission is available at spoken hyphen tutorial dot org slash NMEICT hyphen Intro
+
|More information on this mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
  
 
|-
 
|-
 
| 07:41
 
| 07:41
−
| This is Anjana Nair signing off. Thank you
+
| This is Anjana Nair, signing off. Thank you.
  
 
|}
 
|}

Latest revision as of 15:20, 27 March 2017

Time Narration
00:01 Welcome to the tutorial on for and each Loops in Ruby.
00:05 In this tutorial, we will learn:
00:07 Meaning of the term “loop” . The different kinds of loops in Ruby
00:11 Usage of “for” loop and Usage of “each” looping construct.
00:14 Here, we are using:
00:16 Ubuntu version 12.04
00:19 Ruby 1.9.3
00:22 To follow this tutorial, you must have Internet connection.
00:25 You must also have knowledge of Linux commands, Terminal and Text-editor.
00:30 If not, for relevant tutorials, please visit our website.
00:34 Now, let me explain what is referred to as a “loop” in Ruby.
00:38 A loop is a command or set of commands that are executed a fixed number of times.
00:44 Ruby has the following main looping statements.
00:47 for, each , while, until.
00:50 In this tutorial, we will learn how to use the for and each looping constructs.
00:55 Before we begin, please create the following folders in your home directory-
01:02 ttt, ruby hyphen tutorial, looping hyphen statements.
01:07 Please create the sub-folders as mentioned there.
01:11 Now we have created the requisite folders.
01:13 Let's move ahead.
01:15 The syntax of the “for” loop in Ruby is as follows:
01:19 for “variable” in “a collection of objects”
01:22 ruby code end
01:25 Let us try to understand it with an example.
01:28 Create a new file in gedit as shown in the basic level Ruby tutorials
01:32 and name it for hyphen loop dot rb .
01:36 I already have a working example of the “for” loop.
01:39 You can type the code as we go through this example.
01:44 I have declared a “for” loop in this example.
01:47 We have a set of numbers 1 to 20.
01:50 We declare a variable called “i” within the “for” loop.
01:55 The variable “i” gets initialized to the first element in the set of numbers 1 to 20.
02:00 The “for” loop declaration causes the code to iterate over each element in the set 1 to 20.
02:07 The “puts” method declared within the “for” loop is responsible for generating the output.
02:14 Now, open the terminal and type:
02:17 ruby space for hyphen loop dot rb and see the output.
02:22 The output will be an array of numbers 1 to 20.
02:26 In this example, we declared a “for” loop for an inclusive range.
02:31 It included all numbers from 1 to 20.
02:35 Next, we shall look at implementing the “for” loop for a non-inclusive range.
02:41 Continue to type the next part of the code.
02:44 Non-inclusive means it will not include the last element in the collection of objects.
02:49 Here, “for” loop is implemented for a non-inclusive range of numbers 1 to 20.
02:55 You will notice shortly that the number 20 will not be printed in the output.
02:59 The last number does not get included when you have 3 dots between numbers.
03:04 Now, open the terminal and type: ruby space for hyphen loop dot rb
03:13 and see the output.
03:17 The output will still be an array of numbers but will not include the number 20.
03:22 Now, you should be capable enough to write your own “for” loop.
03:27 The syntax of the “each” loop in Ruby is as follows:
03:31 “a collection of objects” dot each, do item
03:36 ruby code end
03:38 Let us try to understand it with an example.
03:42 Create a new file in gedit as shown in the basic level Ruby tutorials
03:46 and name it each hyphen loop dot rb.
03:50 I already have a working example of the each loop.
03:53 You can type the code as we go through this example.
03:58 I have declared an each loop in this example.
04:03 We have a set of numbers 1 to 20.
04:06 We declare a variable called “i” within the each loop.
04:11 The “i” variable gets initialized to the first element in the set of numbers 1 to 20.
04:17 The each loop declaration causes the code to iterate over each element in the set 1 to 20.
04:23 The puts method declared, within the each loop, is responsible for generating the output.
04:30 Now, open the terminal and type: ruby space each hyphen loop dot rb
04:39 and see the output.
04:43 The output will be an array of numbers 1 to 20.
04:46 In the above example, we declared an each loop for an inclusive range.
04:51 It included all numbers from 1 to 20.
04:54 Next we shall look at implementing the each loop for a non-inclusive range.
05:00 Continue to type this part of the code.
05:04 Non-inclusive means it will not include the last element in the collection of objects.
05:10 Here, an each loop is implemented for a non-inclusive range of numbers 1 to 20.
05:16 You will notice shortly that the number 20 will not be printed in the output.
05:20 The last number does not get included when you have 3 dots between numbers.
05:25 Now, open the terminal and type: ruby space each hyphen loop dot rb
05:34 and see the output.
05:39 Now you should be capable enough to write your own each loop.
05:44 How would we determine which looping construct to choose?
05:48 Let us try to recall the "for" loop construct.
05:53 In the first example, we iterated over a set of numbers from 1 to 20 using for loop.
05:59 Execute: ruby space for hyphen loop dot rb in your terminal, see the output.
06:08 Now, look at the code in gedit.
06:11 When you invoke the for loop, Ruby is actually calling the each method behind the scenes.
06:16 And, calling each or for will generate the same output.
06:21 Since the call to for in turn calls each, it is preferable to use the each loop instead.
06:28 This brings us to the end of this Spoken Tutorial.
06:30 Let's summarize.
06:32 In this tutorial, we have learnt: Usage of for loop
06:35 Usage of each construct
06:38 Reasoning behind using each instead of for
06:41 Examples of using the above looping constructs.
06:45 As an assignment-
06:47 Write a ruby program using the appropriate loop construct
06:50 to create an output of even numbers from a set of numbers, say 1 to 20.
06:56 Watch the video available at the following link.
07:00 It summarizes the Spoken Tutorial project.
07:03 If you do not have good bandwidth, you can download and watch it.
07:08 The Spoken Tutorial project team:
07:11 Conducts workshops using spoken tutorials.
07:14 Gives certificates to those who pass an online test.
07:18 For more details, please write to: contact@spoken-tutorial.org
07:23 Spoken Tutorial project is a part of the Talk to a Teacher project.
07:26 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
07:33 More information on this mission is available at: spoken hyphen tutorial dot org slash NMEICT hyphen Intro.
07:41 This is Anjana Nair, signing off. Thank you.

Contributors and Content Editors

Jyotisolanki, PoojaMoolya, Pratik kamble, Sandhya.np14

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