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Full Discussion: Assign user input to already declared array
Top Forums Shell Programming and Scripting Assign user input to already declared array Post 302553468 by Corona688 on Wednesday 7th of September 2011 05:05:36 PM
Old 09-07-2011
BASH is a string language with weak types, so copying an entire array around like that means having to handle it as a string.

There is an operator to turn an array into one string: "${ARR[*]}" But how're you going to do that when all you have is the name of the array, not the array itself? "${!ARR[*]}" doesn't work, the precedence is wrong, and you can't put the[*] outside it to do it backwards. You could shove it all into an eval, which can accomplish any weird syntax you want, but would be difficult. And then you have to turn it back into an array, wrapping it in another layer of stuff.

It's easy to turn a string into an array, though, and BASH has the ! operator to turn a variable name into a variable string. So why not keep your data as strings for easy retrieval?

Code:
#!/bin/bash

# Not arrays -- just strings.  Split them later.
colors="red blue yellow"
red="cherry fire"
blue="baby sky"
yellow="canary banana"

# This variable is used to read other variables.
name="colors"

while [ ! -z "${!name}" ]
do
        # Fill an array with variable name stored in 'name'.
        # i.e. When it's 'colors', it gets filled with ( red blue yellow )
        ARR=( ${!name} )
        echo "Choose a color counting from 0: ${ARR[*]}"
        read choice
        name="${ARR[$choice]}"
done

This User Gave Thanks to Corona688 For This Post:
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LEARN ABOUT PHP

imagecolorresolvealpha

IMAGECOLORRESOLVEALPHA(3)						 1						 IMAGECOLORRESOLVEALPHA(3)

imagecolorresolvealpha - Get the index of the specified color + alpha or its closest possible alternative

SYNOPSIS

       int imagecolorresolvealpha (resource  $image, int  $red, int  $green, int  $blue, int  $alpha)

DESCRIPTION

	This function is guaranteed to return a color index for a requested color, either the exact color or the closest possible alternative.

PARAMETERS

	      o $
		image -An image resource, returned by one of the image creation functions, such as imagecreatetruecolor(3).

	      o $red
		-Value of red component.

	      o $green
		-Value of green component.

	      o $blue
		-Value of blue component.

	      o $alpha
		- A value between 0 and 127.  0 indicates completely opaque while 127 indicates completely transparent.

	The colors parameters are integers between 0 and 255 or hexadecimals between 0x00 and 0xFF.

RETURN VALUES

	Returns a color index.

EXAMPLES

       Example #1

	      Using imagecoloresolvealpha(3) to get colors from an image

	      <?php
	      // Load an image
	      $im = imagecreatefromgif('phplogo.gif');

	      // Get closest colors from the image
	      $colors = array();
	      $colors[] = imagecolorresolvealpha($im, 255, 255, 255, 0);
	      $colors[] = imagecolorresolvealpha($im, 0, 0, 200, 127);

	      // Output
	      print_r($colors);

	      imagedestroy($im);
	      ?>

	      The above example will output something similar to:

	      Array
	      (
		  [0] => 89
		  [1] => 85
	      )

NOTES

       Note

	      This function requires GD 2.0.1 or later (2.0.28 or later is recommended).

SEE ALSO

       imagecolorclosestalpha(3).

PHP Documentation Group 												 IMAGECOLORRESOLVEALPHA(3)
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