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如何将数组作为函数参数传递？

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如何将数组作为函数参数传递？

尝试了一段时间，尝试将数组作为参数传递，但不管用。我尝试了以下方法：

#! /bin/bash

function copyFiles{
   arr="$1"
   for i in "${arr[@]}";
      do
          echo "$i"
      done

}

array=("one" "two" "three")

copyFiles $array

如果有解释的话答案就更好了。

编辑：基本上，我最终会从另一个脚本文件调用该函数。如果可能的话，请解释一下限制。

答案1

  • 扩展没有索引的数组只会给出第一个元素，使用

    copyFiles "${array[@]}"

    代替

    copyFiles $array

  • 使用 she-bang

    #!/bin/bash

  • 使用正确的函数语法

    有效变体是

    function copyFiles {…}
function copyFiles(){…}
function copyFiles() {…}

    代替

    function copyFiles{…}

  • 使用正确的语法获取数组参数

    arr=("$@")

    代替

    arr="$1"

所以

#!/bin/bash
function copyFiles() {
   arr=("$@")
   for i in "${arr[@]}";
      do
          echo "$i"
      done

}

array=("one 1" "two 2" "three 3")

copyFiles "${array[@]}"

输出是（我的脚本有名称foo）

$ ./foo   
one 1
two 2
three 3

答案2

如果你想传递一个或多个参数和一个数组，我建议对@AB 数组的脚本进行这样的更改
应该是最后的论点和只有一个可以传递数组

#!/bin/bash
function copyFiles() {
   local msg="$1"   # Save first argument in a variable
   shift            # Shift all arguments to the left (original $1 gets lost)
   local arr=("$@") # Rebuild the array with rest of arguments
   for i in "${arr[@]}";
      do
          echo "$msg $i"
      done
}

array=("one" "two" "three")

copyFiles "Copying" "${array[@]}"

输出：

$ ./foo   
Copying one
Copying two
Copying three

答案3

您还可以将数组作为引用传递。即：

#!/bin/bash

function copyFiles {
   local -n arr=$1

   for i in "${arr[@]}"
   do
      echo "$i"
   done
}

array=("one" "two" "three")

copyFiles array

但请注意，对 arr 的任何修改都将对数组进行修改。

答案4

下面是一个稍微大一点的例子。有关解释，请参阅代码中的注释。

#!/bin/bash -u
# ==============================================================================
# Description
# -----------
# Show the content of an array by displaying each element separated by a
# vertical bar (|).
#
# Arg Description
# --- -----------
# 1   The array
# ==============================================================================
show_array()
{
    declare -a arr=("${@}")
    declare -i len=${#arr[@]}
    # Show passed array
    for ((n = 0; n < len; n++))
    do
        echo -en "|${arr[$n]}"
    done
    echo "|"
}

# ==============================================================================
# Description
# -----------
# This function takes two arrays as arguments together with their sizes and a
# name of an array which should be created and returned from this function.
#
# Arg Description
# --- -----------
# 1   Length of first array
# 2   First array
# 3   Length of second array
# 4   Second array
# 5   Name of returned array
# ==============================================================================
array_demo()
{
    declare -a argv=("${@}")                           # All arguments in one big array
    declare -i len_1=${argv[0]}                        # Length of first array passad
    declare -a arr_1=("${argv[@]:1:$len_1}")           # First array
    declare -i len_2=${argv[(len_1 + 1)]}              # Length of second array passad
    declare -a arr_2=("${argv[@]:(len_1 + 2):$len_2}") # Second array
    declare -i totlen=${#argv[@]}                      # Length of argv array (len_1+len_2+2)
    declare __ret_array_name=${argv[(totlen - 1)]}     # Name of array to be returned

    # Show passed arrays
    echo -en "Array 1: "; show_array "${arr_1[@]}"
    echo -en "Array 2: "; show_array "${arr_2[@]}"

    # Create array to be returned with given name (by concatenating passed arrays in opposite order)
    eval ${__ret_array_name}='("${arr_2[@]}" "${arr_1[@]}")'
}

########################
##### Demo program #####
########################
declare -a array_1=(Only 1 word @ the time)                                       # 6 elements
declare -a array_2=("Space separated words," sometimes using "string paretheses") # 4 elements
declare -a my_out # Will contain output from array_demo()

# A: Length of array_1
# B: First array, not necessary with string parentheses here
# C: Length of array_2
# D: Second array, necessary with string parentheses here
# E: Name of array that should be returned from function.
#          A              B             C              D               E
array_demo ${#array_1[@]} ${array_1[@]} ${#array_2[@]} "${array_2[@]}" my_out

# Show that array_demo really returned specified array in my_out:
echo -en "Returns: "; show_array "${my_out[@]}"

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