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awk reverse string

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# 1  
Old 05-06-2013
awk reverse string
Hello,
Can anyone explain for me in this script to reverse the string?
1) the "x=x" part, how it works?
Code:
$ echo welcome | awk '{ for(i=length;i!=0;i--)x=x substr($0,i,1);}END{print x}'
$ emoclew

2) x seems to be an array at the END, but can it automatically print the whole array in awk?
Thanks a lot!
YT
# 2  
Old 05-06-2013
"x" is not an array. x=x substr($0,i,1) means that substr($0,i,1) is appended to the variable x; x=x+something.
This User Gave Thanks to Subbeh For This Post:
yifangt
# 3  
Old 05-06-2013
I see, and I am almost there to catch it.
# 4  
Old 05-06-2013
This reverse line by line
Code:
awk '{ for(i=length;i!=0;i--) x=(x substr($0,i,1))}{print x;x=""}'

No need to wait til END for the printing.
I did add parentheses to see what the x does x=(x substr($0,i,1))
It recreate the word by adding one and one letter in reverse order to the x

Value of x by run in loop
Code:
#0 x=""
#1 x=x+"e" x="e"
#2 x=x+"m" x="em"
#3 x=x+"o" x="emo"
etc

This User Gave Thanks to Jotne For This Post:
yifangt
# 5  
Old 05-06-2013
If you want to reverse a string, here is the best way:
Code:
$ echo welcome | rev
emoclew

These 2 Users Gave Thanks to hanson44 For This Post:
shamrock yifangt
# 6  
Old 05-06-2013
And I see it works fine on multiple lines to Smilie
Code:
echo "toy
home" | rev
yot
emoh

If it cant be done with awk, its not worth doing it Smilie
This User Gave Thanks to Jotne For This Post:
yifangt
# 7  
Old 05-06-2013
Thanks Hanson and Jotne!
I was aware of the rev cmd, but I was trying to catch the awk part. Thanks anyway.
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