對這文章發表回應
發表限制: 非會員 可以發表
發表者： 冷日 發表時間： 2016/4/29 9:33:40
Bash Shell Script Iterate Through Array Values
Posted August 30, 2004 by Quinn McHenry in Bourne shell scripting
Having an array of variables is of no use unless you can use those values somehow. This tech-recipe shows a few methods for looping through the values of an array in the bash shell.
Take, for example, the array definition below:
The following expression evaluates into all values of the array:
It also can be used anywhere a variable or string can be used.
A simple for loop can iterate through this array one value at a time:
This script will loop through the array values and print them out, one per line. Additional statements can be placed within the loop body to take further action, such as modifying each file in an array of filenames.
Sometimes it is useful to loop through an array and know the numeric index of the array you are using (for example, so that you can reference another array with the same index). The same loop in the example above can be achieved this way, too:
In this example, the value ${#names[@]} evaluates into the number of elements in the array (4 in this case). The individual elements of the array are accessed, one at a time, using the index integer $i as ${names[$i]}
原文出處：Bash Shell Script Iterate Through Array Values
Posted August 30, 2004 by Quinn McHenry in Bourne shell scripting
Having an array of variables is of no use unless you can use those values somehow. This tech-recipe shows a few methods for looping through the values of an array in the bash shell.
Take, for example, the array definition below:
names=( Jennifer Tonya Anna Sadie )
The following expression evaluates into all values of the array:
${names[@]}
It also can be used anywhere a variable or string can be used.
A simple for loop can iterate through this array one value at a time:
for name in ${names[@]} do
echo $name
# other stuff on $name
done
This script will loop through the array values and print them out, one per line. Additional statements can be placed within the loop body to take further action, such as modifying each file in an array of filenames.
Sometimes it is useful to loop through an array and know the numeric index of the array you are using (for example, so that you can reference another array with the same index). The same loop in the example above can be achieved this way, too:
for (( i = 0 ; i < ${#names[@]} ; i++ )) do echo ${names[$i]} # yadda yadda done
In this example, the value ${#names[@]} evaluates into the number of elements in the array (4 in this case). The individual elements of the array are accessed, one at a time, using the index integer $i as ${names[$i]}
原文出處：Bash Shell Script Iterate Through Array Values