Shell script - check length when splitting string to array

Question

I am using a bash script and I am trying to split a string with urls inside for example:

str=firsturl.com/123416 secondurl.com/634214

So these URLs are separated by spaces, I already used the IFS command to split the string and it is working great, I can iterate trough the two URLs with:

for url in $str; do
    #some stuff
done

But my problem is that I need to get how many items this splitting has, so for the str example it should return 2, but using this:

${#str[@]}

return the length of the string (40 for the current example), I mean the number of characters, when I need to get 2.

Also iterating with a counter won't work, because I need the number of elements before iterating the array.

Any suggestions?

that other guy · Accepted Answer · 2013-06-28 21:47:28Z

5

Split the string up into an array and use that instead:

str="firsturl.com/123416 secondurl.com/634214"
array=( $str )

echo "Number of elements: ${#array[@]}"
for item in "${array[@]}"
do
  echo "$item"
done

You should never have a space separated list of strings though. If you're getting them line by line from some other command, you can use a while read loop:

while IFS='' read -r url
do
  array+=( "$url" )
done

For properly encoded URLs, this probably won't make much of a difference, but in general, this will prevent glob expansion and some whitespace issues, and it's the canonical format that other commands (like wget -i) works with.

edited Jun 28, 2013 at 21:47

answered Jun 28, 2013 at 4:07

that other guy

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2 Comments

eLRuLL Over a year ago

I am generating the urls from a python script, so I can change it and make it print several lines. How can I get them on an array? could you update that also please?

eLRuLL Over a year ago

I ended up using a multiline file, but the array works great too.

Diego Torres Milano · Accepted Answer · 2013-06-28 04:06:31Z

5

You should use something like this

declare -a a=( $str )
n=${#a[*]} # number of elements

answered Jun 28, 2013 at 4:06

Diego Torres Milano

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Comments

jaypal singh · Accepted Answer · 2013-06-28 04:33:49Z

4

Several ways:

$ str="firsturl.com/123416 secondurl.com/634214"

bash array:

$ while read -a ary; do echo ${#ary[@]}; done <<< "$str"
2

awk:

$ awk '{print NF}' <<< "$str"
2

*nix utlity:

$ printf "%s\n" $(printf "$str" | wc -w)
2

bash without array:

$ set -- $str
$ echo ${#@}
2

edited Jun 28, 2013 at 4:33

answered Jun 28, 2013 at 4:28

jaypal singh

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Comments

dougEfresh · Accepted Answer · 2013-06-28 04:10:36Z

0

If you create a function that will echo $* then that should provide the number of items to split.

count_params () { echo $#; }

Then passing $str to this function will give you the result

str="firsturl.com/123416 secondurl.com/634214"
count_params $str

answered Jun 28, 2013 at 4:10

dougEfresh

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