for databaseName in listOfNames
then
# Do something
end
18 回答
-3
您可以使用 ${arrayName[@]} 的语法
#!/bin/bash
# declare an array called files, that contains 3 values
files=( "/etc/passwd" "/etc/group" "/etc/hosts" )
for i in "${files[@]}"
do
echo "$i"
done
2
试试这个 . 它正在运行和测试 .
for k in "${array[@]}"
do
echo $k
done
# For accessing with the echo command: echo ${array[0]}, ${array[1]}
96
当然,这是可能的 .
for databaseName in a b c d e f; do
# do something like: echo $databaseName
done
arr=("sharlock" "bomkesh" "feluda" ) ##declare array
len=${#arr[*]} # it returns the array length
#iterate with while loop
i=0
while [ $i -lt $len ]
do
echo ${arr[$i]}
i=$((i+1))
done
#iterate with for loop
for i in $arr
do
echo $i
done
#iterate with splice
echo ${arr[@]:0:3}
33
你可以像这样使用它:
## declare an array variable
declare -a arr=("element1" "element2" "element3")
## now loop through the above array
for i in "${arr[@]}"
do
echo "$i"
# or do whatever with individual element of the array
done
# You can access them using echo "${arr[0]}", "${arr[1]}" also
也适用于多行数组声明
declare -a arr=("element1"
"element2" "element3"
"element4"
)
set -- arg1 arg2 arg3 ...
for item ;do
echo "This is item: $item."
done
This is item: arg1.
This is item: arg2.
This is item: arg3.
This is item: ....
请注意,这与
for item in "$@";do
echo "This is item: $item."
done
然后进入一个脚本:
#!/bin/bash
for item ;do
printf "Doing something with '%s'.\n" "$item"
done
将其保存在脚本 myscript.sh , chmod +x myscript.sh 中,然后
./myscript.sh arg1 arg2 arg3 ...
Doing something with 'arg1'.
Doing something with 'arg2'.
Doing something with 'arg3'.
Doing something with '...'.
在函数中相同:
myfunc() { for item;do cat <<<"Working about '$item'."; done ; }
然后
myfunc item1 tiem2 time3
Working about 'item1'.
Working about 'tiem2'.
Working about 'time3'.
7
Yes
for Item in Item1 Item2 Item3 Item4 ;
do
echo $Item
done
输出:
Item1
Item2
Item3
Item4
Over multiple lines
for Item in Item1 \
Item2 \
Item3 \
Item4
do
echo $Item
done
输出:
Item1
Item2
Item3
Item4
Simple list variable
List=( Item1 Item2 Item3 )
要么
List=(
Item1
Item2
Item3
)
Display the list variable :
echo ${List[*]}
出局:
Item1 Item2 Item3
Loop through the list:
for Item in ${List[*]}
do
echo $Item
done
出局:
Item1
Item2
Item3
Create a function to go through a list:
Loop(){
for item in ${*} ;
do
echo ${item}
done
}
Loop ${List[*]}
To preserve spaces ; single or double quote list entries and double quote list expansions :
List=(' Item 1 '
' Item 2'
' Item 3'
)
for item in "${List[@]}";
do
echo "$item"
done
输出:
Item 1
Item 2
Item 3
Using the declare keyword (command) to create the list , which is technically called an array :
declare -a List=(
"element 1"
"element 2"
"element 3"
)
for entry in "${List[@]}"
do
echo "$entry"
done
出局:
element 1
element 2
element 3
Creating an associative array . A dictionary :
declare -A continent
continent[Vietnam]=Asia
continent[France]=Europe
continent[Argentina]=America
for item in "${!continent[@]}";
do
printf "$item is in ${continent[$item]} \n"
done
输出:
Argentina is in America
Vietnam is in Asia
France is in Europe
CVS variables or files in to a list . 将内部字段分隔符从空格更改为您想要的任何内容 . 在下面的示例中,它将更改为逗号
List="Item 1,Item 2,Item 3"
Backup_of_internal_field_separator=$IFS
IFS=,
for item in $List;
do
echo $item
done
IFS=$Backup_of_internal_field_separator
输出:
Item 1
Item 2
Item 3
If need to number them :
`
这被称为后退 . 将命令放在后面 .
`commend`
它位于键盘上的第一个旁边,或者位于Tab键上方 . 在标准的美国英语键盘上 .
List=()
Start_count=0
Step_count=0.1
Stop_count=1
for Item in `seq $Start_count $Step_count $Stop_count`
do
List+=(Item_$Item)
done
for Item in ${List[*]}
do
echo $Item
done
如果您使用的是Korn shell,则有“ set -A databaseName ", else there is " declare -a databaseName ”
编写一个处理所有shell的脚本,
set -A databaseName=("db1" "db2" ....) ||
declare -a databaseName=("db1" "db2" ....)
# now loop
for dbname in "${arr[@]}"
do
echo "$dbname" # or whatever
done
它应该适用于所有炮弹 .
4
本着与4ndrew的回答一样的精神:
listOfNames="RA
RB
R C
RD"
# To allow for other whitespace in the string:
# 1. add double quotes around the list variable, or
# 2. see the IFS note (under 'Side Notes')
for databaseName in "$listOfNames" # <-- Note: Added "" quotes.
do
echo "$databaseName" # (i.e. do action / processing of $databaseName here...)
done
# Outputs
# RA
# RB
# R C
# RD
B.名字中没有空格:
listOfNames="RA
RB
R C
RD"
for databaseName in $listOfNames # Note: No quotes
do
echo "$databaseName" # (i.e. do action / processing of $databaseName here...)
done
# Outputs
# RA
# RB
# R
# C
# RD
# line delimited (each databaseName is stored on a line)
while read databaseName
do
echo "$databaseName" # i.e. do action / processing of $databaseName here...
done # <<< or_another_input_method_here
#!/bin/bash
names="RA
RB
R C
RD"
while read -r line; do
echo line: "$line"
done <<< "$names"
44
单线循环,
declare -a listOfNames=('db_a' 'db_b' 'db_c')
for databaseName in ${listOfNames[@]}; do echo $databaseName; done;
你会得到这样的输出,
db_a
db_b
db_c
152
我遍历我的项目数组以进行 git pull 更新:
#!/bin/sh
projects="
web
ios
android
"
for project in $projects do
cd $HOME/develop/$project && git pull
end
2
声明数组不适用于Korn shell . 对Korn shell使用以下示例:
promote_sla_chk_lst="cdi xlob"
set -A promote_arry $promote_sla_chk_lst
for i in ${promote_arry[*]};
do
echo $i
done
18
每个Bash脚本/会话可能的第一行:
say() { for line in "${@}" ; do printf "%s\n" "${line}" ; done ; }
使用例如:
$ aa=( 7 -4 -e ) ; say "${aa[@]}"
7
-4
-e
可以考虑: echo 将 -e 解释为此处的选项
1
这些答案都不包括反击......
#!/bin/bash
## declare an array variable
declare -a array=("one" "two" "three")
# get length of an array
arraylength=${#array[@]}
# use for loop to read all values and indexes
for (( i=1; i<${arraylength}+1; i++ ));
do
echo $i " / " ${arraylength} " : " ${array[$i-1]}
done
输出:
1 / 3 : one
2 / 3 : two
3 / 3 : three
4
listOfNames="db_one db_two db_three"
for databaseName in $listOfNames
do
echo $databaseName
done
要不就
for databaseName in db_one db_two db_three
do
echo $databaseName
done
1
这也很容易阅读:
FilePath=(
"/tmp/path1/" #FilePath[0]
"/tmp/path2/" #FilePath[1]
)
#Loop
for Path in "${FilePath[@]}"
do
echo "$Path"
done
0
很惊讶没有人发布这个 - 如果你在循环数组时需要元素的索引,你可以这样做:
arr=(foo bar baz)
for i in ${!arr[@]}
do
echo $i "${arr[i]}"
done
输出:
0 foo
1 bar
2 baz
我发现这比"traditional" for-loop风格( for (( i=0; i<${#arr[@]}; i++ )) )更优雅 .
18 回答
您可以使用
${arrayName[@]}
的语法试试这个 . 它正在运行和测试 .
当然,这是可能的 .
有关详细信息,请参阅Bash Loops for, while and until .
简单方法:
你可以像这样使用它:
也适用于多行数组声明
脚本或函数的隐式数组:
除了anubhava的正确答案:如果循环的基本语法是:
bash中有一个特例:
当运行脚本或函数时,在命令行传递的 arguments 将被分配给
$@
数组变量,您可以通过$1
,$2
,$3
等进行访问 .这可以填充(用于测试)
loop over this 数组可以简单地写成:
Note 保留的工作
in
不存在,也没有数组名称!样品:
请注意,这与
然后进入一个脚本:
将其保存在脚本
myscript.sh
,chmod +x myscript.sh
中,然后在函数中相同:
然后
Yes
输出:
Over multiple lines
输出:
Simple list variable
要么
Display the list variable :
出局:
Loop through the list:
出局:
Create a function to go through a list:
To preserve spaces ; single or double quote list entries and double quote list expansions :
输出:
Using the declare keyword (command) to create the list , which is technically called an array :
出局:
Creating an associative array . A dictionary :
输出:
CVS variables or files in to a list .
将内部字段分隔符从空格更改为您想要的任何内容 .
在下面的示例中,它将更改为逗号
输出:
If need to number them :
这被称为后退 . 将命令放在后面 .
它位于键盘上的第一个旁边,或者位于Tab键上方 . 在标准的美国英语键盘上 .
输出是:
Becoming more familiar with bashes behavior :
在文件中创建列表
将列表文件读入列表并显示
BASH commandline reference manual : Special meaning of certain characters or words to the shell.
如果您使用的是Korn shell,则有“ set -A databaseName ", else there is " declare -a databaseName ”
编写一个处理所有shell的脚本,
它应该适用于所有炮弹 .
本着与4ndrew的回答一样的精神:
B.名字中没有空格:
Notes
listOfNames="RA RB R C RD"
具有相同的输出 .引入数据的其他方式包括:
stdin(如下所列),
variables,
an array(接受的答案),
a file ......
从stdin读取
bash IFS "field separator to line" [1]分隔符可以在脚本中指定以允许其他空格(即
IFS='\n'
,或MacOSIFS='\r'
)我也喜欢接受的答案:) - 我已经将这些片段作为其他有用的方式包含在内,也可以回答这个问题 .
在脚本文件的顶部包含
#!/bin/bash
表示执行环境 .花了几个月的时间才弄清楚如何编写这个简单:)
其他来源(while read loop)
这类似于user2533809的答案,但每个文件将作为单独的命令执行 .
单线循环,
你会得到这样的输出,
我遍历我的项目数组以进行
git pull
更新:声明数组不适用于Korn shell . 对Korn shell使用以下示例:
每个Bash脚本/会话可能的第一行:
使用例如:
可以考虑:
echo
将-e
解释为此处的选项这些答案都不包括反击......
输出:
要不就
这也很容易阅读:
很惊讶没有人发布这个 - 如果你在循环数组时需要元素的索引,你可以这样做:
输出:
我发现这比"traditional" for-loop风格(
for (( i=0; i<${#arr[@]}; i++ ))
)更优雅 .(
${!arr[@]}
和$i
不仅仅是数字;有些人会建议引用它们,但这只是个人偏好 . )