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1. UNIX for Dummies Questions & Answers
Hi, I wanted to calculate cumulative frequency distribution of my data that involves several arithmetic calls. I did things in excel but its taking me forever. this is what I want to do:
var1.txt contains n observations which I have to compute for frequency which is given by 1/n and subsequently... (7 Replies)
Discussion started by: ida1215
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2. Shell Programming and Scripting
Hi all,
I am attempting to calculate a running variance for a file containing a column of numbers. I am using the formula variance=sum((x-mean(x))^2)/(n-1), where x is the value on the current row, and mean(x) is the average of all of the values up until that row. n represents the total number... (1 Reply)
Discussion started by: Jahn
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3. Shell Programming and Scripting
I need to find the average from a file like:
data => BW:123 M:30 RTD:0 1 0 1 0 0 1 1 1 1 0 0 1 1 0'
data => BW:123 N:30 RTD:0 1 0 1 0 0 1 1 1 1 0 0 1 1 0'
data => BW:123 N:30 RTD:0 1 0 1 0 0 1 1 1 1 0 0 1 1 0'
data => BW:123 N:30 RTD:0 1 0 1 0 0 1 1 1 1 0 0 1 1 0'
data => BW:123 N:30 RTD:0 1... (4 Replies)
Discussion started by: Slagle
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4. Shell Programming and Scripting
Hi All,
I have the following time stamp data in 2 columns
Date TimeStamp(also with milliseconds)
05/23/2012 08:30:11.250
05/23/2012 08:30:15.500
05/23/2012 08:31.15.500
.
.
etc
From this data I need the following output.
0.00( row1-row1 in seconds)
04.25( row2-row1 in... (5 Replies)
Discussion started by: ks_reddy
5 Replies
5. Shell Programming and Scripting
Hi All,
IS there any 'awk' way to manipulate following data?
Fruit Date Count
Apple 20/08/2011 5
Apple 27/08/2011 7
Apple 05/09/2011 11
Apple 12/09/2011 3
Apple 19/09/2011 25
.
.
.
.
Orange 20/08/2011 9
Orange 27/08/2011 20
Orange 27/08/2011 7
Orange 05/09/2011 15
Orange... (3 Replies)
Discussion started by: aniketdixit
3 Replies
6. Shell Programming and Scripting
I would like to extract a number from $0 and calculate if it can be devided by 25. Though the number can also be less then 25 or bigger than 100. How do i extract the number and how can the integer be calculated?
String:
"all_results">39</span>I am looking for the number between "all_results"> ... (5 Replies)
Discussion started by: sdf
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7. Shell Programming and Scripting
Hey guys, maybe you can help me with this...
I want to read input.dat line by line, while doing a simple calculation between the second column value of the current line and the second column value of the next line (like a difference).
input is something like this:
0 3.945757
1 ... (1 Reply)
Discussion started by: origamisven
1 Replies
8. Shell Programming and Scripting
Hi All,
I have a txt file which has hundreds of lines and 41 fields. I have a requirement to pick up field 14 from the text file which is a date fiels in the following format.
Field 14 :
Data Type : NUMERIC DATE (YYYYMMDD)
Field Length : 8
Example of Data :20090415
Field 42 :
Data Type... (2 Replies)
Discussion started by: nua7
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9. Shell Programming and Scripting
I have about 5000 columns of data that i need to convert all of it into pecentages. for shorter colums i have been using this code:
{print $1/($1+$2)*100,$2/($1+$2),$3/($3+$4)*100 .....}
but this is a teadious process... is there anyway to do it without having to write all of them out?
sample... (20 Replies)
Discussion started by: chronicx
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10. Shell Programming and Scripting
Hello,
With the following small script I list the size of documents belonging to a certain user by each time selecting the bytes-field of that file ($7). Now it fills the array with every file it finds so in the end the output of some users contains up to 200.000 numbers. So how can I calculate... (7 Replies)
Discussion started by: Hille
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A2P(1) Perl Programmers Reference Guide A2P(1)
NAME
a2p - Awk to Perl translator
SYNOPSIS
a2p [options] [filename]
DESCRIPTION
A2p takes an awk script specified on the command line (or from standard input) and produces a comparable perl script on the standard
output.
OPTIONS
Options include:
-D<number>
sets debugging flags.
-F<character>
tells a2p that this awk script is always invoked with this -F switch.
-n<fieldlist>
specifies the names of the input fields if input does not have to be split into an array. If you were translating an awk script that
processes the password file, you might say:
a2p -7 -nlogin.password.uid.gid.gcos.shell.home
Any delimiter can be used to separate the field names.
-<number>
causes a2p to assume that input will always have that many fields.
-o tells a2p to use old awk behavior. The only current differences are:
o Old awk always has a line loop, even if there are no line actions, whereas new awk does not.
o In old awk, sprintf is extremely greedy about its arguments. For example, given the statement
print sprintf(some_args), extra_args;
old awk considers extra_args to be arguments to "sprintf"; new awk considers them arguments to "print".
"Considerations"
A2p cannot do as good a job translating as a human would, but it usually does pretty well. There are some areas where you may want to
examine the perl script produced and tweak it some. Here are some of them, in no particular order.
There is an awk idiom of putting int() around a string expression to force numeric interpretation, even though the argument is always
integer anyway. This is generally unneeded in perl, but a2p can't tell if the argument is always going to be integer, so it leaves it in.
You may wish to remove it.
Perl differentiates numeric comparison from string comparison. Awk has one operator for both that decides at run time which comparison to
do. A2p does not try to do a complete job of awk emulation at this point. Instead it guesses which one you want. It's almost always
right, but it can be spoofed. All such guesses are marked with the comment ""#???"". You should go through and check them. You might
want to run at least once with the -w switch to perl, which will warn you if you use == where you should have used eq.
Perl does not attempt to emulate the behavior of awk in which nonexistent array elements spring into existence simply by being referenced.
If somehow you are relying on this mechanism to create null entries for a subsequent for...in, they won't be there in perl.
If a2p makes a split line that assigns to a list of variables that looks like (Fld1, Fld2, Fld3...) you may want to rerun a2p using the -n
option mentioned above. This will let you name the fields throughout the script. If it splits to an array instead, the script is probably
referring to the number of fields somewhere.
The exit statement in awk doesn't necessarily exit; it goes to the END block if there is one. Awk scripts that do contortions within the
END block to bypass the block under such circumstances can be simplified by removing the conditional in the END block and just exiting
directly from the perl script.
Perl has two kinds of array, numerically-indexed and associative. Perl associative arrays are called "hashes". Awk arrays are usually
translated to hashes, but if you happen to know that the index is always going to be numeric you could change the {...} to [...].
Iteration over a hash is done using the keys() function, but iteration over an array is NOT. You might need to modify any loop that
iterates over such an array.
Awk starts by assuming OFMT has the value %.6g. Perl starts by assuming its equivalent, $#, to have the value %.20g. You'll want to set
$# explicitly if you use the default value of OFMT.
Near the top of the line loop will be the split operation that is implicit in the awk script. There are times when you can move this down
past some conditionals that test the entire record so that the split is not done as often.
For aesthetic reasons you may wish to change index variables from being 1-based (awk style) to 0-based (Perl style). Be sure to change all
operations the variable is involved in to match.
Cute comments that say "# Here is a workaround because awk is dumb" are passed through unmodified.
Awk scripts are often embedded in a shell script that pipes stuff into and out of awk. Often the shell script wrapper can be incorporated
into the perl script, since perl can start up pipes into and out of itself, and can do other things that awk can't do by itself.
Scripts that refer to the special variables RSTART and RLENGTH can often be simplified by referring to the variables $`, $& and $', as long
as they are within the scope of the pattern match that sets them.
The produced perl script may have subroutines defined to deal with awk's semantics regarding getline and print. Since a2p usually picks
correctness over efficiency. it is almost always possible to rewrite such code to be more efficient by discarding the semantic sugar.
For efficiency, you may wish to remove the keyword from any return statement that is the last statement executed in a subroutine. A2p
catches the most common case, but doesn't analyze embedded blocks for subtler cases.
ARGV[0] translates to $ARGV0, but ARGV[n] translates to $ARGV[$n-1]. A loop that tries to iterate over ARGV[0] won't find it.
ENVIRONMENT
A2p uses no environment variables.
AUTHOR
Larry Wall <larry@wall.org>
FILES
SEE ALSO
perl The perl compiler/interpreter
s2p sed to perl translator
DIAGNOSTICS
BUGS
It would be possible to emulate awk's behavior in selecting string versus numeric operations at run time by inspection of the operands, but
it would be gross and inefficient. Besides, a2p almost always guesses right.
Storage for the awk syntax tree is currently static, and can run out.
perl v5.18.2 2014-01-06 A2P(1)