[GRASS-user] for looping using attribute levels of a vector

Dear R-gurus,

I have a vector file which have several attributes.
One of the columns have values that repeat like
the name of city. So, I would like to do some
steps for each level of the column of interest.

Just supose that I have CityA, CityB, CityC

I would like to use this strings on a for loop.

Following suggestions by Hamish, I addapted the
following temptative code:

for MAP in v.db.select map=mymap column=city ; do
echo my steps…
done

But when the first entry on the looping is the name
of the field (City), and when the city have white
space like “Los Angeles”, each word are used
as different entry of MAP variable of the “for” looping.

My questions are:

  1. How can I bypass the problem of “v.db.select” return
    the name of column as first entry
  2. How can I bypass the problem of white space for
    city names?

Best wishes

miltinho astronauta
brazil

Milton Cezar Ribeiro wrote:

Dear R-gurus,

I have a vector file which have several attributes.
One of the columns have values that repeat like
the name of city. So, I would like to do some
steps for each level of the column of interest.

Just supose that I have CityA, CityB, CityC

I would like to use this strings on a for loop.

Following suggestions by Hamish, I addapted the
following temptative code:

for MAP in `v.db.select map=mymap column=city` ; do
  echo my steps...
done

But when the first entry on the looping is the name
of the field (City), and when the city have white
space like "Los Angeles", each word are used
as different entry of MAP variable of the "for" looping.

My questions are:
1. How can I bypass the problem of "v.db.select" return
the name of column as first entry
2. How can I bypass the problem of white space for
city names?

Best wishes

miltinho astronauta
brazil

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1. Looking at the docs -c drops the column name.

2. Hmm, you probably need to find a way to encapsulate each line in
quotes for the loop reads each string or put a delimiter in that you can
parse. maybe try vs="," to add a character.

http://grass.itc.it/grass63/manuals/html63_user/v.db.select.html

Alex

On Sat, 2008-10-11 at 00:55 -0700, Alex Mandel wrote:

Milton Cezar Ribeiro wrote:
> Dear R-gurus,

[...]

> 2. How can I bypass the problem of white space for
> city names?

[...]

2. Hmm, you probably need to find a way to encapsulate each line in
quotes for the loop reads each string or put a delimiter in that you can
parse. maybe try vs="," to add a character.

http://grass.itc.it/grass63/manuals/html63_user/v.db.select.html

Dear Milton, you work under linux, right? Does it work if you use "tr"?
For example:
echo "ano rizoma" | tr ' ' '_'

Regards, Nikos