Help deleting leading zeros in a file


 
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# 1  
Old 09-24-2013
Help deleting leading zeros in a file

I have a list of numbers extracted and need to delete the leading zeros from them, but when i do so, the command I am using also deletes numbers that end in Zero as well. eg 10, 20, 30, etc

this is part of a larger script and the only way I can think of is to try and detect the 10,20 30 etc in the first part of a if statement then deal with the remainder but that i think is quite messy as there may be many of them

Ideas?

My input to check is like this file below and trying to process with this code snipopet
Code:
file="leadingzero.txt"     # input filename
while read line 
    do
        wardevent=${line##*[!1-9]}                     # remove leading Zero from the line
echo $wardevent
done <"$file"

File:
Code:
001
002
003
004
005
006
007
008
009
010
011
012
019
020
021

Thanks
Ken

Last edited by Scott; 09-26-2013 at 08:58 AM.. Reason: Removed attachment; not necessary for such a small file
# 2  
Old 09-24-2013
Input file
Code:
 $ cat file
001
002
003
004
005
006
007
008
009
010
011
012
019
020
021

What is your expected output..?

this one?

Code:
 $ awk '{$1+=0}1' file
1
2
3
4
5
6
7
8
9
10
11
12
19
20
21

or this one....?

Code:
 awk '{sub(/^0/,"")}1' file
01
02
03
04
05
06
07
08
09
10
11
12
19
20
21

Always give your input and desired output.
# 3  
Old 09-24-2013
Sorry for that and thanks
Yes i would like the output without the leading zeros as per this
Code:
$ awk '{$1+=0}1' file

Is there a way to do it using string processing rather than calling awk?
Reason being as the section of the file is only a selection from a much larger line that is processed as part of a much larger string. The rest of the code pulls out the numbers and then I need to stip the leading zeros before putting them in an array.

I only included the extracted part to avoid confusion with the rest of the code.

Ken

Last edited by Scrutinizer; 09-24-2013 at 03:08 PM.. Reason: code tags
# 4  
Old 09-24-2013
How large is the file overall, i.e. number of records?

You could shell script it like this:-
Code:
#!/bin/ksh

typeset -i col1                     # Define as integer

while read col1 rest
do
   echo "$col1 $rest"
done < input_file  > output_file

The run time may get long if the file is large though and you will get errors if any of the values in column1 are not numeric.

Does that work as a quick hit?

Perhaps you could do something with sed or awk to strip leading zeros if the file is bigger and the alapse time of the above code is not acceptable.



I hope that this helps

Robin
Liverpool/Blackburn
UK
# 5  
Old 09-24-2013
also


Code:
while read line 
    do
        wardevent=$(expr $line + 0)                     # remove leading Zero from the line
echo $wardevent
done<file

This User Gave Thanks to pamu For This Post:
# 6  
Old 09-24-2013
Dear pamu,
How does your code react with the following input? :-
Code:
0001
0002 123
0003 Hello

I regret that I get syntax errors for lines 2 & 3.



Robin
This User Gave Thanks to rbatte1 For This Post:
# 7  
Old 09-24-2013
Quote:
Originally Posted by pamu
also


Code:
while read line 
    do
        wardevent=$(expr $line + 0)                     # remove leading Zero from the line
echo $wardevent
done<file

Awesome thank you very much that is exactly what I need to achieveSmilie

Thanks
Ken
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