icon), **number** (
icon), **boolean** (
icon), **null** (
icon) **array** (
icon), and **date** (
icon).
: the operator returns "true" (match) for the value
- 
: the operator returns "false" (doesn't match) for the value
| Example value | Is true | Is false | Is empty | Is not empty | Is null | Is not null |
| :----------------------------: | :---------------------------------------------------------: | :---------------------------------------------------------: | :---------------------------------------------------------: | :---------------------------------------------------------: | :---------------------------------------------------------: | :---------------------------------------------------------: |
| `""` | | | | | | |
| `" "`, `"foo"`, `"null"` | | | | | | |
| `1`; `"1"`; `true`; `"true"` | | | | | | |
| `0`; `"0"`; `false`, `"false"` | | | | | | |
| `-1`; `"-1"` | | | | | | |
| `null` | | | | | | |
| Empty array (`[]`) | | | | | | |
| Non-empty array (at least one item) | | | | | | |
#### Where can I find operators?
Operators can be found across the whole [Decision Hub](/docs/analytics) in which you create analyses based on events, their parameters and profile attributes. Additionally, you can find operators in various filters across the application, for example on the list of profiles, while defining audiences for messages and workflows, where the operators are used in [Profile filters](/docs/analytics/i_client-filter).
You can also find operators while defining filters within item feed, such as defining the [filters for items to be displayed in AI recommendations](/docs/ai-hub/recommendations-v2/recommendation-filters).
{#array}
---
An array is an ordered collection of elements of the same or different type.
- If you want to operate on a value that is already an array of strings, no additional action is required to analyze the value.
- If the array contains different data types (numbers, objects, arrays) it must be [converted into a string](#converting-arrays-into-strings) and analyzed as a string.
#### Converting arrays into strings
{#boolean}
---
This operator type is used in analyses/filters to verify whether an attribute/event parameter/event exists, the value of an attribute is `false` or `true` (string or boolean) or `null`.
This operator type contains the following logical operators:
1. **Is true** - Choose this operator to analyze event parameters and/or attributes whose value is `true` (string) or true boolean (attribute or parameter value sent to Synerise as a boolean value).
2. **Is false** - Choose this operator to analyze event parameters and/or attributes whose value is `false` (string), false boolean (attribute or parameter value sent to Synerise as a boolean value), `null`, empty.
### Null {#null}
---
{#date}
---
This operator can be used only for event parameters and profile attributes whose value is a date/time string formatted according to ISO 8601.
While defining the condition for this operator type, you can select a date from a calendar. All the operators are meant to narrow the scope of dates considered in the general date filter of the analysis/filter.
The screen below presents a segmentation that groups profiles in terms of their date of birth. The conditions of the segmentation uses the Custom logical operator to define the date range for the birth date attribute.
{#number}
---
This operator can be used only for event parameters or attributes whose values are expressed as numbers (including those sent as a string). For example, you can create a following condition: `size more than 8` (analyze the `size` attribute whose value is higher than 8, which is 9, 10, and higher).
This type contains the following logical operators:
1. **Equal** and **Not equal** - Choose these options to check if the attribute is or isn't exactly the same as the value you enter.
2. **Less than** and **More than** - Choose these options to analyze an event parameter or attribute whose value is lower or higher than the provided value (for example, for the following condition - the `size` attribute is `More than 8`, the results will contain entities whose `size` attribute is 8,01 or higher).
3. **Less or equal to** - Choose this option if you want to analyze an event parameter or attribute whose value is lower than or equal to the provided value.
4. **More or equal to** - Choose this option if you want to consider the elements which are equal or bigger than the number you provide.
### Object
---
If you want to analyze an object (a collection of key/value data) in the event parameters, that object must be [converted into a string](#converting-arrays-into-strings) and analyzed as a [string](#string).
### String {#string}
---
This operator can be used with event parameters and attributes whose values is a piece of text. For example,`favoriteBrand equals XYZ`. This type contains the following logical operators:
1. **Equal** and **Not equal** - Choose these options to check if the parameter/attribute value is or isn't the same as the value you enter.
2. **Contain** and **Not contain** - Choose these options to either include or exclude values that contain a specific phrase, respectively.
3. **Starts with** and **Ends with** - Choose these options if you want to include values that start or end with a particular string of characters.
4. **Regular expression** - Choose this option when you want to check if the value of an event parameter or attribute matches a regular expression.