For loops trouble

Ruby
1

I am trying to translate a program I have in Java into ruby and having
trouble translating this for loop
for(int i = 0; a[i] < x;i++)
I tried this
for i in a[i]…x
but it produce some errors. Any help will be appreciated. Thank you.

2

On Sat, Apr 16, 2011 at 1:27 PM, Daniel J.
[email protected]wrote:

numbers = *1…10
max = 6

numbers.each do |num|
break unless num < max
puts num
end

3

On Sat, Apr 16, 2011 at 1:36 PM, Josh C. [email protected]
wrote:

Posted via http://www.ruby-forum.com/.

numbers = *1…10
max = 6

numbers.each do |num|
break unless num < max
puts num
end

I guess, depending on your needs, you might want the index as well, in
which
case

numbers.each do |num|

becomes

numbers.each_with_index do |num, index|

4

On Sat, Apr 16, 2011 at 11:27 AM, Daniel J.
[email protected] wrote:

I am trying to translate a program I have in Java into ruby and having
trouble translating this for loop
for(int i = 0; a[i] < x;i++)
I tried this
for i in a[i]…x
but it produce some errors. Any help will be appreciated. Thank you.

A simple literal translation goes from this:

for (int i=0; a[i] < x; i++) { … }

to this Ruby:

i = 0
while a[i] < x
…
i += 1
end

That Ruby is almost certainly not the best way to translate the Java
loop, but the best way really depends on what you are doing in the
loop.

5

On Sun, Apr 17, 2011 at 2:27 AM, Daniel J. [email protected]
wrote:

for(int i = 0; a[i] < x;i++)

there are many ways.
eg,

x
=> 6
a
=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
a.take_while{|e| e<x}
=> [1, 2, 3, 4, 5]
a.each_with_index.take_while{|e| e<x}
=> [[1, 0], [2, 1], [3, 2], [4, 3], [5, 4]]

kind regards -botp

6

Daniel J. wrote in post #993238:

I am trying to translate a program I have in Java into ruby and having
trouble translating this for loop
for(int i = 0; a[i] < x;i++)
I tried this
for i in a[i]…x
but it produce some errors. Any help will be appreciated. Thank you.

Ruby has a for-in loop:

a = [2, 4, 1, 9, 6]
x = 7

for num in a
break if num > x
puts num
end

But a for-in loop calls each(), so ruby programmers just call each()
directly:

a.each do |num|
break if num > x
puts num
end

I tried this
for i in a[i]…x

If a[i] = 4, and x = 7, then you are traversing the range 4…7. Also,
your variable names would cause confusion: i for the element and i for
the index.