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Niugg2010
Obsidian | Level 7

 X=”GTTCACTAGCAACCTCAAACAGACACCATGGTGCACCTG”

 

a=”-CCTCA”

b=”A-CTCA”

c=”AC-TCA”

d=”ACC-CA”

e=”ACCT-A”

f=”ACCTC-”

 

“-“ is any one letter, such as “G” “T” or “A”;

I thought a,b,c,d,e,f are all equal to pattern “ACCTCA”

How can I write an index function to find the position of a (or b, or c, or d, or e, or f) in X; 

 

Thanks.

1 ACCEPTED SOLUTION

Accepted Solutions
Patrick
Opal | Level 21

You say "pattern" I think RegEx. Below a variation of what has already been proposed.

data sample;
  input string:$60.;
  match_pos= prxmatch('/(.CCTCA|A.CTCA|AC.TCA|ACC.CA|ACCT.A|ACCTC.)/oi',string);
  match_flg= prxmatch('/(.CCTCA|A.CTCA|AC.TCA|ACC.CA|ACCT.A|ACCTC.)/oi',string)>0;
  datalines;
GTTCACTAGCAACCTCAAACAGACACCATGGTGCACCTG
GTTCACTAGCACACTCAAACAGACACCATGGTGCACCTG
;
run;

View solution in original post

7 REPLIES 7
LaurieF
Barite | Level 11

I'm no great Perl maven, but using prxmatch will give you what you're after. Here's how I did it:

 

data _null_;
infile cards;
retain x "GTTCACTAGCAACCTCAAACAGACACCATGGTGCACCTG";
length pattern $ 9;
input pattern;
match = prxmatch('/' || strip(pattern) || '/', x);
put match=;
cards;
.CCTCA
A.CTCA
AC.TCA
ACC.CA
ACCT.A
ACCTC.
;
run;

In Perl, the wild card is '.', not '-'.

 

When this code is run, the pattern is found at position 12 every time. If it weren't found, like with index, it would return 0.

Niugg2010
Obsidian | Level 7

Thanks a lot. I never used prxmatch function. I will try it.

Patrick
Opal | Level 21

find() or index() don't allow for wildcard searches.

 

You could either use a Regular Expression or a Like operator in a where clause.

 

Would you just need the first position where one of your patterns matches? And would ALL patterns have to match or only one of them?

Reeza
Super User

Also, look into COMPGED, Complev and other functions. 

Not sure they'll give you enough control though. 

Niugg2010
Obsidian | Level 7

 X=”GTTCACTAGCAACCTCAAACAGACACCATGGTGCACCTG”
pattern="ACCTCA" or pattern="A-CTCA"


Actually I want to check " if X contains pattern "; 
I found I can not  use this logistic judgement,

So I thought maybe I can use index() function,

if result >0 it means X contains pattern;

if result =0 it means X does not contains pattern.

 

if someone can suggest a better method, it will be great. 

Patrick
Opal | Level 21

You say "pattern" I think RegEx. Below a variation of what has already been proposed.

data sample;
  input string:$60.;
  match_pos= prxmatch('/(.CCTCA|A.CTCA|AC.TCA|ACC.CA|ACCT.A|ACCTC.)/oi',string);
  match_flg= prxmatch('/(.CCTCA|A.CTCA|AC.TCA|ACC.CA|ACCT.A|ACCTC.)/oi',string)>0;
  datalines;
GTTCACTAGCAACCTCAAACAGACACCATGGTGCACCTG
GTTCACTAGCACACTCAAACAGACACCATGGTGCACCTG
;
run;
Niugg2010
Obsidian | Level 7

Thanks a lot. It is very helpful.

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