如何从bash中的字符串数组中提取数值

Question

如果数组 = ["stack","overflow","5","6","question","9"]

我想制作另一个数组来存储所有数值，例如： new_arr = [5,6,9] in bash。

Answer 1

在bash 中，您可以这样做：

# declare original array
arr=("stack" "overflow" "5" "6" "question" "9")

# remove all elements that have at least one non-digit character
narr=(${arr[@]//*[!0-9]*})

# check content of narr
declare -p narr

输出：

declare -a narr='([0]="5" [1]="6" [2]="9")'

Answer 2

在带有 cmets 内联的纯 bash 中：

#!/bin/bash

# the initial array
array=( "stack" "overflow" "5" "6" "question" "9" )

# declare the final array
declare -a new_arr

# loop over the original values
for val in "${array[@]}"
do
    # use regex to filter out those with only digits
    if [[ $val =~ ^[0-9]+$ ]];
    then
        # and append them to new_arr
        new_arr+=($val)
    fi
done

# print the result
for val in "${new_arr[@]}"
do
    echo $val
done

---

如果 array 是标量

array='["stack","overflow","5","6","question","9"]'

你应该使用解析器。 sed 用于通用流编辑，jq 是专门用于处理 JSON 数据的解析器。

这里 jq 用于仅选择那些包含至少 1 个字符且所有字符必须是数字的值，使用 regex ^[0-9]+$：

readarray new_arr < <(echo "$array" | jq -r '.[] | select(test("^[0-9]+$"))')

Answer 3

使用 for 循环，您将能够遍历数组，然后通过 this post 获得灵感来确定迭代器的值是数字还是字符串。

如果是数值，只需将其附加到另一个数组即可。

Answer 4

与nodejs：

正确输入的正确工具：

array = ["stack","overflow","5","6","question","9"]

#!/bin/bash

arr=( $(
    node<<EOF
    new_arr = ["stack","overflow","5","6","question","9"]
    .filter(e => e.match(/^d+$/));
    new_arr.forEach(e => console.log(e))
EOF
)) 
printf '%s
' "${arr[@]}" # plain bash array

在线测试

new_arr = ["stack","overflow","5","6","question","9"]
.filter(e => e.match(/^d+$/));
new_arr.forEach(e => console.log(e))