From: hanmac@...
Date: 2019-12-03T12:10:38+00:00
Subject: [ruby-core:96077] [Ruby master Bug#16395] .any? and .all? methods,	flawed.

Issue #16395 has been updated by Hanmac (Hans Mackowiak).


your problem is that `.any?` and `.all?` wants a value returned for the block which is truly or falsely 

puts returns nil which is falsely, in the second example count += 1 returns an integer which is truly

----------------------------------------
Bug #16395: .any? and .all? methods, flawed.
https://bugs.ruby-lang.org/issues/16395#change-82927

* Author: stiuna (Juan Gregorio)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: 2.6.5
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN
----------------------------------------
The dynamics of the script is simple, no explanations needed, look for yourselves:

``` ruby
#                 100E1       312A3 8B64  282F   C4A  B28F 
result = '99E2E403100E1A685A63312A308B6478282F2B2C4A34B28F7E'
virus = ['100E1', '312A3', '8B64', '282F', 'C4A', 'B28F']

count = 0
virus.all? {|i|
    puts i
    if result.include? i
        count += 1
    end
}

puts "Coincidences: #{count}"
```

Out:

```
100E1
312A3
8B64
282F
C4A
B28F
Coincidences: 6
```

That's correct. Now change .all? for .any?

Out:

```
100E1
Coincidences: 1
```

That's not right. Now let's modify the .any? block like this:

``` ruby
virus.any? {|i|
    if result.include? i
        count += 1
        puts "#{count}:#{i}"
    end
}
```

Out:

```
1:100E1
2:312A3
3:8B64
4:282F
5:C4A
6:B28F
Coincidences: 6
```

That's correct. Now change .any? for .all?

Out:

```
1:100E1
Coincidences: 1
```

That's not right. Now let's modify the .all? block like this:

``` ruby
virus.all? {|i|
    if result.include? i
        puts "#{count}:#{i}"
        count += 1
    end
}
```

Out:

```
0:100E1
1:312A3
2:8B64
3:282F
4:C4A
5:B28F
Coincidences: 6
```

That's correct. If you look only I have changed the order of the instructions puts and count.

In case you don't understand me, I'll put the complete code with each method:

``` ruby
result = '99E2E403100E1A685A63312A308B6478282F2B2C4A34B28F7E'
virus = ['100E1', '312A3', '8B64', '282F', 'C4A', 'B28F']

count = 0
virus.any? {|i|
    if result.include? i
        # If these two lines change order the program fails.
        count += 1
        puts "#{count}:#{i}"
    end
}

puts "Coincidences: #{count}"
```

**The output will print 6 coincidences, but if you change the order of the instructions puts and count the program returns 1 coincidence.**

Now with .all?

``` ruby
result = '99E2E403100E1A685A63312A308B6478282F2B2C4A34B28F7E'
virus = ['100E1', '312A3', '8B64', '282F', 'C4A', 'B28F']

count = 0
virus.all? {|i|
    if result.include? i
        # If these two lines change order the program fails. Compare the order with .any?
        puts "#{count}:#{i}"
        count += 1
    end
}

puts "Coincidences: #{count}"
```

**The output will print 6 coincidences, but if you change the order of the instructions puts and count the program returns 1 coincidence.**




-- 
https://bugs.ruby-lang.org/

Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe>
<http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>