AWK using an array to subscript an array??

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2 total messages Started by Anthony P Scott Fri, 04 Sep 1992 00:40

#1119

Author: Anthony P Scott
Date: Fri, 04 Sep 1992 00:40

75 lines
1200 bytes

Say for instance that I wanted to read a line of text containing
one character and output
that line in terms of the postion of the letters in the 
alphabet.

ie  like:

 a
 b
 c
 d
 e
 f
 g
 h
 i
 j
 k
 l
 m
 n
 o
 p
 q

would be printed as:
1
 2
 3
 4
 5
 6
 7
 8
 9
 10
 11
 12
 13
 14
 15
 16
 17 

One way I visualized doing this is to read the alphabet into an array
such as:

alph[a] = 1
alph[b] = 2
alph[c] = 3
...

...
alph[q] = 20

and then read the line of text into another array by

{
line_arr[NR] = $1
}

 and then using something like

for (i=i; i<=NR; i++) {
alph_pos[i] = alph[line_arr[i]]
print alph_pos[i]
}

However this doesn't work.

Does any body have any suggestions?

Thanks in anticipation.

Tony Scott

Re: AWK using an array to subscript an array??

#1120

Author: Sani Nassif [227]
Date: Fri, 04 Sep 1992 11:51

71 lines
1985 bytes

Anthony P Scott (aps583@huxley.anu.edu.au) wrote (with some edits):
: Say for instance that I wanted to read a line of text containing
: one character and output that line in terms of the postion of the
: letters in the alphabet.
: 
: ie  like:
:  a
:  b
:  c
:  d
: 
: would be printed as:
:  1
:  2
:  3
:  4
: 
: One way I visualized doing this is to read the alphabet into an array
: such as:
: 
: alph[a] = 1
: alph[b] = 2
: alph[c] = 3
: ...
: 
: and then read the line of text into another array by
: 
: {
:     line_arr[NR] = $1
: }
: 
:  and then using something like
: 
: for (i=1; i<=NR; i++) {
:     alph_pos[i] = alph[line_arr[i]]
:     print alph_pos[i]
: }
: 
: However this doesn't work. Does any body have any suggestions?
: Thanks in anticipation.
: 
: Tony Scott

For one thing, you might want to try to have the array contain
the "string" alphabets:

 alph["a"] = 1
 alph["b"] = 2
 alph["c"] = 3

Otherwist, AWK will just put zeros for a, b, c assuming they are
variables. In general, a program to do this might look like:

BEGIN	{
    while (getline < INDEXFILE > 0) {
	index[$1] = ++N
    }
}

{
    print index[$1]
}

where INDEXFILE is passed in pointing to some file that has
your "alphabet".

Sani.
----------------------------------------------------------------------
Sani R. Nassif
(sani.nassif@att.com)
----------------------------------------------------------------------

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