## Comparison

Several built-in, infix operators allow testing for equality and inequality. For numbers, `<`

, `>`

, `<=`

, `>=`

, `==`

, and `!=`

are used. For strings, `eq`

, `neq`

, and `like`

are used.

The following are all valid predicate expressions:

c == 5
page:var("city") eq "Blackfoot"
"Lindon" neq location:city()
weather:curr_temp() < 90
location:city() + ", WA" eq city
5 * (weather:curr_temp() - 32) / 9 < 0 |

As can be seen from the preceding examples, a number of built-in libraries provide predicates that can be used inside predicate expressions. The documentation for those libraries gives details about their operation.

Two special comparison operators are useful with the sort() operator: `<=>`

and `cmp`

. These operators return -1 if the first operand is less than the second, 0, if they're equal, and 1 if the first operand is greater than the second.The `<=>`

operator is used with numbers and `cmp`

is used with strings.

x = 5;
y = 6;
x <=> y // returns -1
x <=> x // returns 0
y <=> x // returns 1
p = "aab";
q = "abb";
a cmp b // returns -1
a cmp a // returns 0
b cmp a // returns 1 |

## Like

`Like`

takes a regular expression as its second argument and returns true if it matches the string given as its first argument. Arguments to these operators can be any valid expression.

spicy = cheese like re/(nacho|pepperjack)/; |

Note that when the `like` operator is used inside a JSONPath expression, the second operand, representing the regular expression, is given as a string. `'/(nacho|pepperjack)/'` |

## Membership

There is an infix operator for testing membership, `><`

. The >< operator tests the number or string in the right operand for membership in the map or array given by the left operand. For maps, membership extends to keys only.

a = [5, 6, 7];
m = {"a" : 1, "b" : 2};
a >< 6 // returns true
a >< 3 // returns false
m >< "a" // returns true
m >< "foo" // returns false |

## Compound Predicates

Compound predicate expressions are created using the operators `&&`

, `||`

, and `not`

to express conjunction, disjunction, and negation, respectively. Conjunction has precedence over disjunction. Parentheses are used to group expressions for precedence.

not a
a && b
a || b
(a || b ) && not c |