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How to read a number from a file?

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# 1  
Old 03-26-2015
How to read a number from a file?
hello guys,

I'm struggled to get a number from a very long text file.
Code:
 NAtoms=   33 NActive=   30 NUniq=   23 SFac= 1.00D+00 NAtFMM=   60 NAOKFM=F Big=F
 Integral buffers will be    131072 words long.
 Raffenetti 2 integral format.

The number 33 is what I wanted, always follows NAtoms= . I use awk -F= '{print $2}', but get "33 NActive" instead of 33.

Thank you very much for your kind help.
# 2  
Old 03-26-2015
Hello liuzhencc,

Following may help you in same with provided example.
Code:
awk -F"=" '/^NAtoms/ {sub(/^[[:space:]]+/,X,$2);sub(/[[:alpha:]]+/,X,$2);print $2}' Input_file

Thanks,
R. Singh
# 3  
Old 03-26-2015
Quote:
Originally Posted by RavinderSingh13
Hello liuzhencc,

Following may help you in same with provided example.
Code:
awk -F"=" '/^NAtoms/ {sub(/^[[:space:]]+/,X,$2);sub(/[[:alpha:]]+/,X,$2);print $2}' Input_file

Thanks,
R. Singh
Hi Singh,
can you exdplain your answer word by word?
awk -F"=" '/^NAtoms/ {sub(/^[[:space:]]+/,X,$2);sub(/[[:alpha:]]+/,X,$2);print $2}'
# 4  
Old 03-26-2015
Quote:
Originally Posted by liuzhencc
hello guys,

I'm struggled to get a number from a very long text file.
Code:
 NAtoms=   33 NActive=   30 NUniq=   23 SFac= 1.00D+00 NAtFMM=   60 NAOKFM=F Big=F
 Integral buffers will be    131072 words long.
 Raffenetti 2 integral format.

The number 33 is what I wanted, always follows NAtoms= . I use awk -F= '{print $2}', but get "33 NActive" instead of 33.

Thank you very much for your kind help.
Don't set field sep -F=, modify like this

Code:
awk '/NAtoms/{print $2}' infile

This User Gave Thanks to Akshay Hegde For This Post:
liuzhencc
# 5  
Old 03-26-2015
Hello kenshinhimura,

Following is the explaination for same, hope this helps.
Code:
awk 
-F"="                                  #### Take = as delimiter
'/^NAtoms/                         #### Search those lines which are starting from word NAtoms
{sub(/^[[:space:]]+/,X,$2);  #### substitute leading space of $2 with NULL 
sub(/[[:alpha:]]+/,X,$2)       #### substitute all alphabates in $2 with NULL so only digits will come as result 
;print $2}'                          #### print $2 now. 
test4523                            #### Input_file

Thanks,
R. Singh
# 6  
Old 03-26-2015
Quote:
Originally Posted by Akshay Hegde
Don't set field sep -F=, modify like this

Code:
awk '/NAtoms/{print $2}' infile

Great! it simply does the trick!
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