Use shell array, good, keep learning later

I don't know when I wrote something, But I was found by archaeology when I sorted out the documents. I just smiled at those people who were bored. If the errors in this article cause all mental losses to you, contact the insurance company! Of course you can tell me (Talk To Me)

Array as a special {
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} "> Data structures have a place in any programming language. Of course, bash {
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{
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} "> Shell is no exception. This article makes a small summary of the shell array.
Here we will only discuss the situation of one-dimensional arrays, with regard to multi-dimensional arrays (in fact, you have to use a one-dimensional array method to simulate), not involved. This includes array copying, calculation, deletion, and replacement.

Array declaration:

1. 1) array [Key] = value # array [0] = one, array [1] = two

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1. 2) declare-A array # array is treated as the array name

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1. 3) array = (value1 value2 value3 ...)

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1. 4) array = ([1] = one [2] = two [3] = three ...)

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1. 5) array = "One Two Three" # echo $ {array [0 | @ | *]}. The array variable is treated as an array, but the array element only contains the string itself.

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Array access:

1. 1) $ {array [Key] }#$ {array [1]}

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Delete An Array

1. 1) unset array [1] # Delete the first element in the array

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1. 2) unset array # Delete the entire array

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Calculate the length of the array:

1. 1) $ {# array}

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1. 2) $ {# array [0]} # Same as above. $ {# Array [*]} and $ {# array [@]}. Note the difference between # {array: 0} and # {array: 0 }.

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Array Extraction
Extract from the tail:
Array = ([0] = one [1] = two [2] = three [3] = Four)
$ {Array [@]: 1} # two three four. After removing all elements from the first element, $ {array [@]: 0} indicates all elements.
$ {Array [@]: 0: 2} # One Two
$ {Array [@]: 1: 2} # two three

Delete a substring

1. [Root @ localhost Dev] # echo $ {array [@]: 0}
2. One two three four

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1. [Root @ localhost Dev] # echo $ {array [@] # T * e} # Start the shortest match on the left: "T * E", which matches "thre"
2. One Two e four

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1. [Root @ localhost Dev] # echo $ {array [@] # T * e} # The longest match from the left, which matches "three"

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1. [Root @ localhost Dev] # array = ([0] = one [1] = two [2] = three [3] = Four)

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1. [Root @ localhost Dev] # echo $ {array [@] % O} # minimum matching from the end of a string
2. One TW three four

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1. [Root @ localhost Dev] # echo $ {array [@] % O} # longest match starting from the end of the string
2. One TW three four

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Substring replacement

1. [Root @ localhost Dev] # array = ([0] = one [1] = two [2] = three [3] = Four)

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The first matched one will be deleted.

1. [Root @ localhost Dev] # echo $ {array [@]/O/m}
2. Mne twm three fmur

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All matched items will be deleted.

1. [Root @ localhost Dev] # echo $ {array [@] // o/m}
2. Mne twm three fmur

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If the child string is not specified, the matched child string is deleted.

1. [Root @ localhost Dev] # echo $ {array [@] // o /}
2. Ne TW three fur

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Replace the first terminal string

1. [Root @ localhost Dev] # echo $ {array [@]/# O/k}
2. Kne two three four

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Terminal string after replacement string

1. [Root @ localhost Dev] # echo $ {array [@]/% O/k}
2. One twk three four

Copy code $ Arr = (123 34 3 5)
$ Echo $ arr // obtain the first element by default.
> 123
$ Echo $ {arr [1]} // access through subscript
> 34
$ Echo $ {arr [@]} // access the entire array, @ or * get the entire array
> 123 34 3 5
$ Echo $ {# arr [@]} // obtain the length of the array (maximum subscript), # obtain the length array is the last subscript
> 3
$ Echo $ {# arr [3]} // obtain the string length
> 1
$ Echo $ {arr [@]: 1: 2} // obtain part of the array content by Slicing
> 34 3
$ Echo $ {arr [@]: 2} // starts with the second element.
> 3 5
$ Echo $ {arr [@]: 2} // to the second element
> 123 34
Reference http://www.tech-recipes.com/rx/642/bash-shell-script-accessing-array-variables/
Array simulation operation
Http://www.tech-recipes.com/rx/911/queue-and-stack-using-array/
Push:
Array = ("$ {array [@]}" $ new_element)
Pop:
Array = ($ {array [@]: 0 :$ ($ {# array [@]}-1 ))})
Shift:
Array = ($ {array [@]: 1 })
Unshift
Array = ($ new_element "$ {array [@]}")
Function del_array {
Local I
For (I = 0; I <$ {# array [@]}; I ++ ))
DoS
If ["$1" = "$ {array [$ I]}"]; then
Break
Fi
Done
Del_array_index $ I
}
Function del_array_index {
Array = ($ {array [@]: 0: $1 }$ {array [@]: $($1 + 1 ))})
}