05-14-2009
Quote:
Originally Posted by
colemar
Yes, I forgot that print$0 is the default action.
Can you tell whether !(FNR in a) is any better than !a[FNR] performancewise?
Actually.... I read somewhere (c.l.a most likely) that the 'lookup' is generally slower than the direct 'value fetch and comparison', but I don't quite remember for what version of awk.
Me personally I'm just more accustomed to think of 'array membership' rather than 'value fetch' - just a matter of taste I reckon.
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LEARN ABOUT DEBIAN
pamdeinterlace
pamdeinterlace(1) General Commands Manual pamdeinterlace(1)
NAME
pamdeinterlace - remove ever other row from a PAM/PNM image
SYNOPSIS
pamdeinterlace [-takeodd] [-takeeven] N [infile]
You can use the minimum unique abbreviation of the options. You can use two hyphens instead of one. You can separate an option name from
its value with white space instead of an equals sign.
DESCRIPTION
pamdeinterlace Removes all the even-numbered or odd-numbered rows from the input PNM or PAM image. Specify which with the -takeeven and
-takeodd options.
This can be useful if the image is a video capture from an interlaced video source. In that case, each row shows the subject 1/60 second
before or after the two rows that surround it. If the subject is moving, this can detract from the quality of the image.
Because the resulting image is half the height of the input image, you will then want to use pamstretch or pnmscale to restore it to its
normal height:
pamdeinterlace myimage.ppm | pamstretch -yscale=2 >newimage.ppm
OPTIONS
-takeodd
Take the odd-numbered rows from the input and put them in the output. The rows are numbered starting at zero, so the first row in
the output is the second row from the input. You cannot specify both -takeeven and -takeodd.
-takeeven
Take the even-numbered rows from the input and put them in the output. The rows are numbered starting at zero, so the first row in
the output is the first row from the input. This is the default. You cannot specify both -takeeven and -takeodd.
SEE ALSO
pamstretch(1), pnmscale(1)
AUTHOR
put by Bryan Henderson in the public domain in 2001
11 November 2001 pamdeinterlace(1)