# Writing expressions

GDevelop supports expressions! Expressions are dynamic values that can be used in event parameters. For example, to set an object position, you can use a fixed number as `75`

or you can use an expression such as `AnotherObject.X() - Variable(position_offset)`

.

There are two types of expressions:

**Numerics**Numerics can be used in event parameters. They receive a numeric value such as object position, z-order, variable number, etc.

**Strings**Strings can be used in parameters that receive a text/string value. You can use this expression to read the content of a text object string, it's color, the text of another variable, etc.

## Numeric expressions

As stated above, Numeric expressions can be used in numeric parameters.

### Random values

`Random(max)`

- Returns an integer between `0`

and the `max`

value that is defined. The “range” is [0, max].

*Examples using the Random() Expression:*

Random(3) // The 3 possible integer values are 0, 1, 2, and 3

`RandomInRange(min, max)`

- Returns an integer between `min`

and `max`

. The “range” is [min, max].

*Examples using the RandomInRange() Expression:*

RandomInRange(-1, 2) // The 4 possible values are are -1, 0, 1, and 2 // Note that "RandomInRange(min, max)" is equivalent to "min + Random(max - min)": -1 + Random(2 - -1) // This gives the same results as above

`RandomFloat(max)`

- Returns a float between `0`

and `max`

. The range is `[0, max)`

. Note that `max`

is not included in the range. It's important to also note that the possible results are infinite. This is because there are infinite real numbers between any two different values.

*Examples using the RandomFloat(max) Expression:*

RandomFloat(2.5) //SOME of the many possible values are 0, 1.467798, 2.000587, and 2.499999

`RandomFloatInRange(min, max)`

- Returns a float between `min`

and `max`

. The range is `[min, max]`

. Note that `max`

is not included in the range. It's important to also note that the possible results are infinite as there are infinite real numbers between any two different values.

*Examples using the RandomFloatInRange() Expression:*

RandomFloatInRange(-1.5, 2) //SOME of the many possible values are -1.5, -0.598156, 1.000874 and 1.99999

`RandomWithStep(min, max, step)`

- Returns a number between `min`

and `max`

in steps. The range is `[min, min + N*step]`

with `min + N*step ≤ max < min + (N+1)*step`

. It means it can return any of the stepped values that are less than or equal than `max`

.

*Examples using the RandomWithStep(min, max, step) Expression:*

RandomWithStep(1, 3, 0.6) // The generated numbers are ``1``, ``1.6``, ``2.2`` and ``2.8``