Bash 脚本中的数组元素
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Array elements in Bash scripts
提问by camdixon
How can I use an if statement such as this to compare the element value to a variable. For example i'm going through an array of numbers, and checking the minimum. I'm having syntax problems.
如何使用诸如此类的 if 语句将元素值与变量进行比较。例如，我正在查看一组数字，并检查最小值。我有语法问题。
for ((j=0;j<$i;j++)); do
if [ "$array[$j]" -gt $min ]; then
min=${array[$j]}
fi
done
echo The minimum number is $min
回答by Alexander L. Belikoff
Your ifstatement lacks thenclause:
你的if陈述缺少then条款：
if [ "$array[$j]" -gt $min ]; then
min=${array[$j]}
fi
Also, in the true spirit of UNIX tools, consider something more elegant:
此外，本着 UNIX 工具的真正精神，考虑一些更优雅的东西：
min_elem=$(echo ${array[@]} | tr ' ' '\n' | sort -n | head -1)
回答by Idriss Neumann
Several comments:
几条评论：
- See this answerto know when and how to protect your variables ;
-gtisn't the desired operator for getting the min
- 请参阅此答案以了解何时以及如何保护您的变量；
-gt不是获得最小值所需的运算符
Here's a simple corrected example (just Bash without other commands) :
这是一个简单的更正示例（只是 Bash 没有其他命令）：
#!/bin/bash
array=("1" "0" "2")
length="${#array[@]}"
min="${array[0]}"
for (( i=1 ; i < "$length"; i++)); do
[[ ${array[$i]} -le $min ]] && min="${array[$i]}"
done
echo "The minimum number is $min"
EDIT : Test performed after the comment of gniourf_gniourf (see the comments)
编辑：在 gniourf_gniourf 评论后执行的测试（见评论）
[ ~]$ cat test.sh
#!/bin/bash
array=("1" "0" "2")
m=${array[0]}; for i in "${array[@]:1}"; do ((i<m)) && m=$i; done
echo "The minimum number is $m"
[ ~]$ ./test.sh
The minimum number is 0
[ ~]$ vi test.sh
[ ~]$ cat test.sh
#!/bin/bash
array=("1" "0" "2")
m="${array[0]}"; for i in "${array[@]:1}"; do [[ $i -le $m ]] && m="$i"; done
echo "The minimum number is $m"
[ ~]$ ./test.sh
The minimum number is 0
[ ~]$
