Is a similar statement in the Koran or in Islamic writings?
Is a similar statement in Hindu writings?

There is a remarkable parallelism in the world's great religions:

You shall love your neighbour as yourself.  
JUDAISM: Leviticus 19.18  

Treat others as thou wouldst be treated by thyself. 
SIKHISM: Adi Grandth 

Desire not for anyone the things that ye would not desire for
yourselves.
BAHÁ'Í FAITH: Gleanings 66   

That nature is only good when it shall not do unto another whatever is
not good for its own self.
ZOROASTRIANISM: Dadistan-i-Dinik 

All things whatsoever ye would that men should do to you, do ye even
so to them: for this is the law and the prophets.
CHRISTIANITY: Matthew 7.12   

Not one of you is a believer until he loves for his brother what he
loves for himself.
ISLAM: Forty Hadith of an-Nawawi 

Hurt not others with that which pains yourself. 
BUDDHISM: Udana 5.13  

Regard your Neighbour's gain as your own gain and your neighbour's
loss as your own loss.
TAOISM:T'ai Shang Kan Ying P'ien 

Never do to others what would pain thyself. 
HINDUISM: Panchatantra 3.104   

Do not do to others what you do not want them to do to you. 
CONFUCIANISM: Analects 15.23 

Carlisle Bahá'í Group
http://www.bci.org/carlisle/truths.html

Another Hindu precept that is very similar:

Men gifted with intelligence and purified souls should always treat
others as they themselves wish to be treated. (Mahabharata 13.115.22)

The True Light
http://www.thetruelight.net/SiteExplanation/quest/questofeveryheart3.htm

Search terms used:

"love thy neighbor as thyself" + "islam"
"love your neighbor as yourself" + "islam"
"love thy neighbor as thyself" + "hinduism"
"love your neighbor as yourself" + "hinduism"

Thanks for asking a very interesting question. If anything above is
unclear, or if a link does not function, please request clarification
*before* rating my answer so that I may offer further assistance.

Namaste.
pinkfreud

Excellent!  Just what I was hoping for, but in far greater detail than I expected.

Wow, pinkfreud-ga, 

That was an amazing answer!:) Thanks for looking all of those up, it
was really interesting to read! I hope the customer is equally
pleased.

Judaism also has a rabbinic paraphrase of the Leviticus quote, in the
Talmud, Tractate Shabbat 31a. The great Hillel was asked by a
potential convert to teach him the whole Torah while standing on one
foot. Hillel replied, "What is hateful to you, do not do to your
neighbor. That's the whole Torah; all the rest is commentary. Go study
it!"

--ravuri-ga

Many thanks for the five-star rating and the very generous tip!

~pinkfreud