Top Forums UNIX for Dummies Questions & Answers Basic arithmetic operation with awk? Post 302962864 by Don Cragun on Saturday 19th of December 2015 03:15:22 PM
Quote:
Originally Posted by RudiC
Different approach, not sure if better/faster:
Code:
awk '
        {n = split ($2, T, "[+-]")
         gsub (/[0-9]*/, _, $2)
         split ($2, S, "")
         for (t in T) $2 = $2 + sprintf ("%f", S[t]"1" * T[t])
        }
1
' FS="|" OFS="|" file
rec_10|1
rec_20|10
rec_30|911
rec_40|-911

This is a nice approach, and works fine with gawk and other awk implementations that use FS="" to split each input character into a field. A similar approach that doesn't depend on this behavior (which the standards say produces unspecified results) would be:
Code:
awk '
        {n = split($2, T, "[+-]")
         split($2, S, "[0-9.]+")
	 $2 = 0
         for(i = 1; i < n; i++) $2 = $2 + sprintf ("%f", S[i+1]"1" * T[i])
        }
1
' FS="|" OFS="|" file

which also has a little feature creep allowing a decimal point to be included in the input numbers (sparked by RudiC's code using %f instead of %d in the sprintf() format string).

If you change:
Code:
         gsub (/[0-9]*/, _, $2)

in RudiC's script to:
Code:
         gsub (/[0-9.]*/, _, $2)

his script will also handle floating point values in awk versions where:
Code:
         split ($2, S, "")

doesn't produce a syntax error.
This User Gave Thanks to Don Cragun For This Post:
 
Test Your Knowledge in Computers #481
Difficulty: Medium
Generally speaking, programs do not start out as source code.
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Simple arithmetic operation

I have no idea why I can't get this to work, if anybody can help i would appreciate it. #!/bin/bash x=`cat counter.txt | wc -l` y= '$x / 7' printf "%d People have visited this page" $y :confused: (2 Replies)
Discussion started by: paladyn_2002
2 Replies

2. Shell Programming and Scripting

Help with arithmetic operation

I am using egrep to extract numbers from a file and storing them as variables in a script. But I am not able to do any arithmetic operations on the variables using "expr" because it stores them as char and not integers. Here is my code and the error I get. Any help will be appreciated. #!/bin/sh... (3 Replies)
Discussion started by: emjayshaikh
3 Replies

3. UNIX for Dummies Questions & Answers

arithmetic operation on two columns

Hi, All, I have a file, its content is as follows: 100 150 120 135 140 170 I want to insert a column, its content is determined by the difference between the two values in the same line, if the difference is less than 20, the new value is 1, otherwise is 0. after the operation, the... (1 Reply)
Discussion started by: Jenny.palmy
1 Replies

4. Shell Programming and Scripting

How to perform arithmetic operation on date

Hi all, I would appreciate if anyone knows how to perform adding to date. As for normal date, i can easily plus with any number. But when it comes to month end say for example 28 Jun, i need to perform a plus with number 3, it will not return 1 Jul. Thanks in advance for your help. (4 Replies)
Discussion started by: agathaeleanor
4 Replies

5. Shell Programming and Scripting

Arithmetic operation with awk

I have output like following in a file usmtnz-dinfsi19 72 71 38 1199 1199 0.8 19:23:58 usmtnz-dinfsi19 72 71 38 1199 1199 0.8 19:24:04 (9 Replies)
Discussion started by: fugitive
9 Replies

6. Shell Programming and Scripting

Arithmetic operation between columns using loop variable

Hi I have a file with 3 columns. say, infile: 1 50 68 34 3 23 23 4 56 ------- ------- I want to generate n files from this file using a loop so that 1st column in output file is (column1 of infile/(2*n+2.561)) I am doing like this: for ((i=1; i<=3; i++)) do a=`echo... (3 Replies)
Discussion started by: Surabhi_so_mh
3 Replies

7. Shell Programming and Scripting

floating point arithmetic operation error

I am writing a script in zsh shell, it fetchs a number from a file using the awk command, store it as a variable, which in my case is a small number 0.62000. I want to change this number by multiplying it by 1000 to become 620.0 using the command in the script var2=$((var1*1000)) trouble is... (2 Replies)
Discussion started by: piynik
2 Replies

8. Shell Programming and Scripting

Arithmetic operation in variable

Hi, Here is the script i try to perform arithmetic operation in two variables . git branch -r | while read brname ; do REV_COMMITS=`git rev-list --count $brname` echo "$brname has $REV_COMMITS" (( TOTAL = TOTAL + REV_COMMITS )) echo "in loop" $TOTAL done echo "total is " $TOTAL ... (3 Replies)
Discussion started by: greet_sed
3 Replies

9. Shell Programming and Scripting

Using awk to do arithmetic operation

Hi, I've this following text file FileVersion = 1.03 Filetype = meteo_on_curvilinear_grid TIME = 0 hours since 2016-10-03 12:00:00 +00:00 -6.855 -6.828 -6.801 -6.774 -6.747 -6.719 -6.691 -6.663 -6.634 -6.606 -6.577 -6.548 -6.519 -6.489 TIME = 0 hours since... (2 Replies)
Discussion started by: xisan
2 Replies

10. How to Post in the The UNIX and Linux Forums

How to get defined precision after arithmetic operation using syncsort?

I have to do some arithmetic operation on Field 8 which is calculated by Field 9/Field 7 Suppose i have data like : 0800123456|JAN|2017|JAN|2018|0800123456|0|0.0000|0.00| 0800234567|JAN|2017|JAN|2018|0800234567|4|2.5812|10.32| 0800666666|JAN|2017|JAN|2018|0800666666|2|1.7255|3.45|... (0 Replies)
Discussion started by: pumrao
0 Replies

Featured Tech Videos

All times are GMT -4. The time now is 03:50 AM.
Unix & Linux Forums Content Copyright 1993-2020. All Rights Reserved.
Privacy Policy