如何从Shell中的数组中选择随机项目

问题描述

我正在用Shell脚本创建一个机器人:

I'm creating a bot in Shell Script:

# Array with expressions
expressions=("Ploink Poink" "I Need Oil" "Some Bytes are Missing!" "Poink Poink" "Piiiip Beeeep!!" "Hello" "Whoops! I'm out of memmory!")

# Seed random generator
RANDOM=$$$(date +%s)

# Loop loop loop loop loop loop ...
while [ 1 ]
do
    # Get random expression...
    selectedexpression=${expressions[$RANDOM % ${#RANDOM[*]}]}

    # Write to Shell
    echo $selectedexpression


    # Wait an half hour
    sleep 1 # It's one second for debugging, dear SOers
done

我希望它每秒从expressions打印一个随机项目.我试过了，但是没有用.每次仅打印第一个(Ploink Poink).谁能帮我吗?谢谢

I want that it prints a random item from the expressions every second. I tried this but it does not work. It only prints the first one (Ploink Poink) every time. Can anyone help me out?Thanks

推荐答案

将定义selectedexpression的行更改为

selectedexpression=${expressions[$RANDOM % ${#expressions[@]} ]}

您希望您在expression中的索引是一个从0到expression数组长度的随机数.这样就可以了.

You want your index into expression to be a random number from 0 to the length of the expression array. This will do that.

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