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## Boolean Operators

XPath provides several boolean operators. They’re all straightforward (in XPath 1.0, anyway), so we’ll just list them here.

### Note

When you’re working with boolean expressions in XPath, remember that the values `'true'` and `'false'` are just strings. If you need to use the boolean values, use the functions `true()` and `false()`. Simply using `true` in an XPath expression means a node whose name is `true`, which is almost certainly not what you want. To emphasize the point, we’ll refer to the boolean values with their functions.

As we saw in the section on mathematical operators, converting `true()` and `false()` to numbers returns `1` and `0`, respectively. XPath defines rules for converting different datatypes to boolean values. See Converting to boolean values” in Chapter 5 for all the details.

### Comparing expressions

There are several operators from XPath 1.0 (and 2.0) that compare expressions. We’ll look at those here:

`=` (equal)

Given two expressions, returns `true()` if the two expressions evaluate to the same value, and returns `false()` otherwise.

`!=` (not equal)

Given two expressions, returns `true()` if the two expressions do not evaluate to the same value, and returns `false()` otherwise.

`<` or `&lt;` (less than)

Given two expressions, returns `true()` if the first expression evaluates to a value less than the second. Otherwise, it returns `false()`. The less than operator is usually escaped with `&lt;` so that it doesn’t look like the opening arrow of an XML tag.

`<=` or `&lt;=` (less than or equal)

Given ...

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