numeric.md

title	section
Numeric types	docs

There are two numeric types in JSON Schema: integer and number. They share the same validation keywords.

JSON has no standard way to represent complex numbers, so there is no way to test for them in JSON Schema.

integer[#integer]

The integer type is used for integral numbers. JSON does not have distinct types for integers and floating-point values. Therefore, the presence or absence of a decimal point is not enough to distinguish between integers and non-integers. For example, 1 and 1.0 are two ways to represent the same value in JSON. JSON Schema considers that value an integer no matter which representation was used.

[tabs-start "Language-specific info"] [tab "Python"] In Python, "integer" is analogous to the int type. [tab "Ruby"] In Ruby, "integer" is analogous to the Integer type. [tab "Objective-C"] In Objective-C, "integer" is analogous to the NSInteger type. [tab "Swift"] In Swift, "integer" is analogous to the Int type.

[tabs-end]

// props { "isSchema": true }
{ "type": "integer" }

// props { "indent": true, "valid": true }
42

// props { "indent": true, "valid": true }
-1

Numbers with a zero fractional part are considered integers:

// props { "indent": true, "valid": true }
1.0

Floating point numbers are rejected:

// props { "indent": true, "valid": false }
3.1415926

Numbers as strings are rejected:

// props { "indent": true, "valid": false }
"42"

number[#number]

The number type is used for any numeric type, either integers or floating point numbers.

[tabs-start "Language-specific info"] [tab "Python"] In Python, "number" is analogous to the float type. [tab "Ruby"] In Ruby, "number" is analogous to the Float type. [tab "Objective-C"] In Objective-C, "number" is analogous to the double or NSNumber type. [tab "Swift"] In Swift, "number" is analogous to the Double type.

[tabs-end]

// props { "isSchema": true }
{ "type": "number" }

// props { "indent": true, "valid": true }
42

// props { "indent": true, "valid": true }
-1

Simple floating point number:

// props { "indent": true, "valid": true }
5.0

Exponential notation also works:

// props { "indent": true, "valid": true }
2.99792458e8

Numbers as strings are rejected:

// props { "indent": true, "valid": false }
"42"

Multiples

Numbers can be restricted to a multiple of a given number, using the multipleOf keyword. It may be set to any positive number.

// props { "isSchema": true }
{
  "type": "number",
  "multipleOf" : 10
}

// props { "indent": true, "valid": true }
0

// props { "indent": true, "valid": true }
10

// props { "indent": true, "valid": true }
20

// props { "indent": true, "valid": false }
23

The multiple can be a floating point number:

// props { "isSchema": true }
{
  "type": "number",
  "multipleOf" : 0.01
}

// props { "indent": true, "valid": true }
4.02

// props { "indent": true, "valid": false }
4.021

The JSON Specification allows an arbitrary implementation of the multipleOf keyword and is not constrained by the floating-point behavior of most programming languages. In contrast, most programming languages adhere to the IEEE754 standard for floating-point numbers, which can result in discrepancies between validation according to the JSON Specification and the behavior in programming languages.

Range[#range]

Ranges of numbers are specified using a combination of the minimum and maximum keywords, (or exclusiveMinimum and exclusiveMaximum for expressing exclusive range).

If x is the value being validated, the following must hold true:

x ≥ minimum
x > exclusiveMinimum
x ≤ maximum
x < exclusiveMaximum

While you can specify both of minimum and exclusiveMinimum or both of maximum and exclusiveMaximum, it doesn't really make sense to do so.

// props { "isSchema": true }
{
  "type": "number",
  "minimum": 0,
  "exclusiveMaximum": 100
}

Less than minimum:

// props { "indent": true, "valid": false }
-1

minimum is inclusive, so 0 is valid:

// props { "indent": true, "valid": true }
0

// props { "indent": true, "valid": true }
10

// props { "indent": true, "valid": true }
99

exclusiveMaximum is exclusive, so 100 is not valid:

// props { "indent": true, "valid": false }
100

Greater than maximum:

// props { "indent": true, "valid": false }
101

[tabs-start "Draft-specific info"] [tab "Draft 4"] In JSON Schema Draft 4, exclusiveMinimum and exclusiveMaximum work differently. There they are boolean values, that indicate whether minimum and maximum are exclusive of the value. For example:

if exclusiveMinimum is false, x ≥ minimum
if exclusiveMinimum is true, x > minimum.

This was changed to have better keyword independence.

Here is an example using the older Draft 4 convention:

// props { "isSchema": true }
{
  "type": "number",
  "minimum": 0,
  "maximum": 100,
  "exclusiveMaximum": true
}

Less than minimum:

// props { "indent": true, "valid": false }
-1

exclusiveMinimum was not specified, so 0 is included:

// props { "indent": true, "valid": true }
0

// props { "indent": true, "valid": true }
10

// props { "indent": true, "valid": true }
99

exclusiveMaximum is true, so 100 is not included:

// props { "indent": true, "valid": false }
100

Greater than maximum:

// props { "indent": true, "valid": false }
101

[tabs-end]