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Read CSV column value based on column name


 
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# 1  
Old 11-15-2009
Read CSV column value based on column name

Hi All,

I am newbie to Unix I ve got assignment to work in unix

can you please help me in this regard

There is a sample CSV file
"Username", "Password"
"John1", "Scot1"
"John2", "Scot2"
"John3", "Scot3"
"John4", "Scot4"

If i give the column name as Password and row number as 4 the result I should get '

'Scot3'

can you please help me in writing shell script for the above

Thanks
John
# 2  
Old 11-15-2009
What have you tried so far?
# 3  
Old 11-15-2009
I'm assuming this is homework?

First, do you understand how to pass arguments to your script? Do you know what $1, $2 are inside your script?

Next, you need to know how to extract a specific line by number. I realize that the man pages of "sed" are confusing, so to get you going, try
Code:
sed -n '4p'

Finally, you need to know how to extract the specific column you want, How will you do that? There are at least two general ways to approach that:

You could build a table that matches column names to a number. Your script would have something like

Code:
if [ $1 = "Username" ]
then
Column=1
elif  [ $1 = "Password" ]
then
Column=2
fi
echo $Column

More flexible would be if your script looked up the desired index by examining the first line itself. A crude method:

Code:
read line
Wanted=$1
set $line
if [ $Wanted = $1 ]
then
Column=1
...

There are more clever ways to do that - Google for "Awk Associative Arrays" and see if that gives you any ideas in this vein.

I hope this gets you started. Let's see you write some code and we can help you over the rough spots.
# 4  
Old 11-20-2009
Thank Tony ,

I have tried the following code giving error , please do the needful
John.csv is the file name

If i give the column name as Password and row number as 4 the result I should get '

'Scot3'



Code:
cat John.csv if [ $1 = "Username" ]
then
  Column=1
elif  [ $1 = "Password" ]
then
  Column=2
fi
echo $Column
read line
Wanted=$1
set $line
if [ $Wanted = $1 ]
then
  Column=1
else 
  echo "Hello"
fi


Thanks and Regards,
John

Last edited by Franklin52; 11-20-2009 at 06:23 AM.. Reason: Please indent your code and use code tags!

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