Split a string by anything other than spaces

Monday, May 19, 2014 perl 0 Comments

Have you ever tried this. Dont go on writing big perl code for this. Here's a simple solution for this.

my @arr=split /\S+/,$str;

where
$str is your string
\s obviously matches a white space character. But \S matches a non white space character.
So \S+ matches atleast one non white space character.

Find and replace a string in c++

Monday, May 19, 2014 c , c++ 0 Comments

This can be handy many a times when you are working on a C++ application. There is a no direct method in the standard to do the same except when you are using a boost library. Below is a simple function that I use regularly in my applications which comes in handy for me all the time

template<class T>
int inline findAndReplace(T& source, const T& find, const T& replace)
{
    int num=0;
    int fLen = find.size();
    int rLen = replace.size();
    for (int pos=0; (pos=source.find(find, pos))!=T::npos; pos+=rLen)
    {
        num++;
        source.replace(pos, fLen, replace);
    }
    return num;
}

Inserting lines in a file using Perl

Wednesday, May 14, 2014 perl 0 Comments

I have input file that look's like :

cellIdentity="42901"
cellIdentity="42902"
cellIdentity="42903"
cellIdentity="52904"

Numbers inside the quotes can be anything. The output needed is original line followed by the copy of same line except the last digit of the number should be a series of 5,6,7. So the output should look like below:

cellIdentity="42901"
cellIdentity="42905"
cellIdentity="42902"
cellIdentity="42906"
cellIdentity="42903"
cellIdentity="42907"
cellIdentity="52904"
cellIdentity="52905"

Below is the Perl command that I have written.

perl -pe 'BEGIN{$n=4}$n++;
          $n>7?$n=5:$n;
          $a=$_;print $a;
          s/(\d).$/$n."\""/ge'

Comparing two files using awk - An assignement

Monday, May 12, 2014 awk , nawk 0 Comments

This is an awk assignment given to one of my friend. Its quite challenging. We have two files: File1:(List of companies)

Joe's Garage
Pip Co
Utility Muffin Research Kitchen

File2:(List of payments and dues of the companies in File1)

Pip Co                          $20.13   due
Pip Co                          $20.3   due
Utility Muffin Research Kitchen $2.56    due
Utility Muffin Research Kitchen 2.56    due
Joe's Garage                    $120.28  due
Joe's Garage                    $100.24 payment

Now the challenge is we need to create an output file which states the total amount due by each company. Additionally there is one more requirement where we need to handle the format errors in teh File2.

1. The list of fomrat errors to be handled are:
2. The dollor symbol not present in the amount

If any of the above format errors are encountered, then the complete line should be ignored and proceed to the next line.
The expected output here is:

Joe's Garage $20.04
Utility Muffin Research Kitchen $2.56
Pip Co $20.13

Below is the awk script that I have written for this. and its working at my side.

{
   if(FNR==NR)
   {
          for(i=1;i<=NF;i++)
          str=str","$i;
          a[str]=1;str="";
          next;
   }
   {
   if($(NF-1)!~/^\$/)
   {
   print "Format Error!-No dollor sign"FNR,FILENAME,$(NF-1);
   next;
   }
   if($(NF-1)!~/\.[0-9][0-9]$/)
   {
   print "Format Error!-should have 2 digits after a decimal point"FNR,FILENAME,$(NF-1);
   next;
   }
   for(i=1;i<(NF-1);i++)str=str","$i;
   if(a[str]){
   gsub(/\$/,"",$(NF-1));
   if($NF~/payment/){
     a[str]-=$(NF-1);}
   else if($NF~/due/){
     a[str]+=$(NF-1);}
   }
   str="";
  }
}
END{ 
   for(i in a)
   {
    t=i;
    gsub(/,/," ",t);
    print t,"$"(a[i]-1);
   }
}

I am sure that this can be optimized. I put it long so that its more convincing to all. Below is the way we have to execute this. I am using nawk on solaris.Others can use awk itself. Copy the above code in a file and name it as mycode.awk and then execute the awk command as below:

nawk -f mycode.awk File1 File2

Out that I have got with the above command is:

> nawk -f temp.awk temp2 temp1
Format Error!-should have 2 digits after a decimal point2 temp1 $20.3
Format Error!-No dollor sign4 temp1 2.56
 Joe's Garage $20.04
 Utility Muffin Research Kitchen $2.56
 Pip Co $20.13
>

Joining lines using Awk

Friday, May 02, 2014 awk 1 Comments

Let's say I have a input file which looks like below:

Apr 24 2014;
is;
a;
sample;
;
Jun 24 2014 123;
may 25 2014;
is;
b;
sample;
;
Dec 21 2014 987

I want to merge 6 lines at a time. Which means my output should look like:

Apr 24 2014;is;a;sample;;Jun 24 2014 123
may 25 2014;is;b;sample;;Dec 21 2014 987

Below is a simple command that I would use:

awk '{ORS=(NR%6?"":RS)}1' file

Explanation:
By doing,

ORS=(NR%6?"":RS)

I am setting the output record separator to actual record separator only if line number is a multiple of 6.