您了解了如何把数据重定向到stdin或stdout,如何使用管道,以及如何在UNIX中使用操作符;这些都有助于您编写出更强大的脚本,更好地捕捉错误,使逻辑更简洁清晰。
Knowing how to redirect data as stdin or stdout, how to use the pipe, and how to use operators in UNIX helps you write more powerful scripts with better error trapping and cleaner logic.
它们通常(但不总是)通过对象实例使用对象操作符来调用的。
They are usually — but not always — called via an object instance using the object operator.
你也可以使用这个操作符来从一个列表中解出头和尾。
You can also use this operator to extract the head and tail of a list.
现在通过另一个示例了解为什么可能要使用NOT操作符。
Let's look at another example of why we might use the not operator.
可以使用NOT 操作符对访问控制进行进一步限制。
Using the NOT operator, further restriction can be placed on access control.
需要能够通过使用SQLJOIN操作符来获得这些信息。
The information needed can be obtained by using the SQL JOIN operator.
可以使用+操作符连接多个字符串字面值。
To concatenate multiple String literals, use the + operator.
DB 2使用XSCAN操作符来遍历XML文档树,如需要,还将计算谓词和提取文档片断和值。
DB2 USES the XSCAN operator to traverse XML document trees and, if needed, to evaluate predicates and extract document fragments and values.
使用PEARDB模块和pdo抽象层的另一个价值在于您可以在sql语句中使用?操作符。
The other value in using the abstraction layers of the PEAR DB module and PDO is that you can use the? Operator in your SQL statements.
可以使用通配符和取反操作符!
You can use wildcards, along with the not operator,!, allowing for complex selection criteria.
或者,还是使用“|”操作符,command的输出可以成为另一个程序的标准输入,如下所示。
Or, the command's output can become the standard input for another program, again using the "|" operator like this.
可以通过使用Boolean AND操作符将这两个查询限制组合在该查询中。
These two query restrictions are combined in this query by using the Boolean AND operator.
在清单6中,可以看到组合集合(使用+操作符)和访问成员(通过[position])是多么容易,没有什么值得操心的东西!
In Listing 6, you can see how easy it is to combine collections (using the + operator) and access members (via [position]) — and do so without the fear of things blowing up on you!
summarize方法是通过Dictionary实例使用对象操作符调用的。
The summarize method is invoked via a Dictionary instance using the object operator.
使用dot操作符可以访问或设置hash中的每个属性(参见清单2)。
Each attribute in the hash can be accessed or set using the dot operator (as shown in Listing 2).
可以使用. .操作符来指定整形的范围。
You can specify ranges of integers using the.. operator like so.
拥有构造函数之后,就可以使用new操作符来创建对象了,如下所示
Once I have a constructor function, I can use the new operator to create objects, as shown below
使用“site: ”操作符可以只在指定网站内搜索。
Use the "site:" operator to search only within a certain website.
因此,要判断某个值是否是dictionary中的键,应该使用in操作符检查这个值是否在调用keys方法所返回的键值列表中。
Therefore, to determine if a value is a key within a dictionary, you use the in operator to test whether the key is in the list of key values returned by calling the keys method.
请注意如何使用 <<操作符来代替add()方法。
Notice how you can use the << operator instead of the add() method.
通过在awk语句中使用NOT操作符,可以指定不应该提取哪些记录。
By using the NOT operator with awk, you can specify what records should NOT be extracted from the report.
下面通过一个示例看看使用NOT操作符的sugroups的效果。
Let's look at an example at how sugroups using the NOT operator might be effective.
可以使用Transform操作符来调节ForEach操作的结果。
A Transform operator can be used to modulate the result of the ForEach operation.
要使用表子查询,需要使用SQL操作符将嵌入式查询与布尔表达式组合在一起。
To use a table subquery, you need to use an SQL operator to combine the embedded query with a Boolean expression.
后面的示例将使用这些操作符。
要在对这样的情况使用更多选择的匹配,需要在搜索关键词中使用强制操作符(+)或显式的逻辑操作符(AND)。
To get a more selective match for such cases, use either the enforce operator (+) or an explicit Boolean operator (AND) in the keyword search.
如果您读过我以前的文章(参见参考资料),就会注意到我喜欢使用逻辑操作符,而不是编写多行代码。
If you've read any of my previous articles (see Resources), you'll notice that I favor logical operators over writing several lines of code.
将操作符类与访问方法结合使用,可以指定创建索引和优化查询时使用的操作符。
An operator class is used in conjunction with the access method to specify the operators used for building the index and during query optimization.
可以按照与其他操作符相同的格式使用比较测试操作符。
You use the same format on comparison test operators as other operators.
如果指定了索引名的话,它将对特定的xml索引使用XISCAN操作符来请求一个访问计划。
If specified, it requests an access plan using an XISCAN operator over this particular XML index.
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