# 循环语句loop

## 标准循环

为了保持简洁,重复的任务可以用以下简写的方式:

```
- name: add several users
  user: name={{ item }} state=present groups=wheel
  with_items:
     - testuser1
     - testuser2
```

如果你在变量文件中或者 ‘vars’ 区域定义了一组YAML列表,你也可以这样做:

```
vars:
  somelist: ["testuser1", "testuser2"]
tasks:
  -name: add several user
   user: name={{ item }} state=present groups=wheel
   with_items: "{{somelist}}"
```

使用 ‘with\_items’ 用于迭代的条目类型不仅仅支持简单的字符串列表.如果你有一个哈希列表,那么你可以用以下方式来引用子项:

```
- name: add several users
  user: name={{ item.name }} state=present groups={{ item.groups }}
  with_items:
    - { name: 'testuser1', groups: 'wheel' }
    - { name: 'testuser2', groups: 'root' }
```

注意：如果同时使用 when 和 with\_items （或其它循环声明）,`when`声明会为每个条目单独执行.请参见 the\_when\_statement 示例.

## 嵌套循环

循环也可以嵌套:

```
- name: give users access to multiple databases
  mysql_user: name={{ item[0] }} priv={{ item[1] }}.*:ALL append_privs=yes password=foo
  with_nested:
    - [ 'alice', 'bob' ]
    - [ 'clientdb', 'employeedb', 'providerd']
```

或者

```
- name: give users access to multiple databases
  mysql_user: name={{ item.0 }} priv={{ item.1 }}.*:ALL append_privs=yes password=foo
  with_nested:
    - [ 'alice', 'bob' ]
    - [ 'clientdb', 'employeedb', 'providerd']
```

## 对哈希表使用循环

```
---
vars:
  users:
    alice:
      name: Alice Appleworth
      telephone: 123-456-7890
    bob:
      name: Bob Bananarama
      telephone: 987-654-3210
tasks:
  - name: Print phone records
    debug: msg="User {{ item.key }} is {{ item.value.name }} ({{ item.value.telephone }})"
    with_dict: "{{users}}"
```

## 对文件列表使用循环

with\_fileglob 可以以非递归的方式来模式匹配单个目录中的文件.如下面所示:

```
tasks:

    # first ensure our target directory exists
    - file: dest=/etc/fooapp state=directory

    # copy each file over that matches the given pattern
    - copy: src={{ item }} dest=/etc/fooapp/ owner=root mode=600
      with_fileglob:
        - /playbooks/files/fooapp/*
```


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