Shell Script Array Usage Summary _linux shell

Array as a data structure, in some high-level languages are directly provided and implemented, of course, my shell is also some ha.

PS: This article is written because brother B in the group sent a screenshot:

My big B elder brother is still omnipotent talent ha ... Cut the crap and talk about it.

1, how to declare an array variable?

Direct assignment:

Copy Code code as follows:

array[0]= "Zero" array[1]= "one" array[2]= "two"

Declare statement:

Copy Code code as follows:

Declare-a Array

Parenthesis Space Method:

Copy Code code as follows:

Array= (Zero one Two)

Quotation mark Space Method:

Copy Code code as follows:

Array= "Zero One Two"

Mixing method:

Copy Code code as follows:

array= ([0]= "Zero" [1]= "one" [2]= "two")

2, how to traverse an array?

Standard for loop:

Copy Code code as follows:

[Chenqing@qing ~] for ((i=0;i<${#array [@]};i++)) do echo ${array[i]}; Done
Zero
One
Two

For...in:

Copy Code code as follows:

[chenqing@qing ~] for i in ${array[@]};d o echo $i;d one
Zero
One
Two

3, get the length of the array

Copy Code code as follows:

[chenqing@qing ~] echo ${#array [@]}
3
[chenqing@qing ~] echo ${#array [*]}
3

4. Delete array elements

Copy Code code as follows:

[chenqing@qing ~] unset array[0]
[chenqing@qing ~] echo ${#array [@]}
2
[chenqing@qing ~] for i in ${array[@]};d o echo $i;d one
One
Two

5, delete the array

Copy Code code as follows:

unset array

6, like the Python slice

Copy Code code as follows:

[chenqing@qing ~] Echo ${array[@]:0:1}
Zero
[chenqing@qing ~] Echo ${array[@]:0:2}
Zero One
[chenqing@qing ~] Echo ${array[@]:0:3}
Zero One Two
[chenqing@qing ~] Echo ${array[@]:1}
One Two
[chenqing@qing ~] Echo ${array[@]:2}
Two