MATLAB Function Reference |

Test to determine if all elements are nonzero

**Syntax**

**Description**

```
B = all(A)
```

tests whether *all* the elements along various dimensions of an array are nonzero or logical true (`1`

).

If `A`

is a vector, `all(A)`

returns logical true (`1`

) if all of the elements are nonzero, and returns logical false (`0`

) if one or more elements are zero.

If `A`

is a matrix, `all(A)`

treats the columns of `A`

as vectors, returning a row vector of `1`

s and `0`

s.

If `A`

is a multidimensional array, `all(A)`

treats the values along the first non-singleton dimension as vectors, returning a logical condition for each vector.

`B = all(A,`

tests along the dimension of

)
*dim*`A`

specified by scalar

.*dim*

**Examples**

then `B = (A < 0.5)`

returns logical true (`1`

) only where `A`

is less than one half:

The `all`

function reduces such a vector of logical conditions to a single condition. In this case, all(B) yields `0`

.

This makes `all`

particularly useful in `if`

statements,

where code is executed depending on a single condition, not a vector of possibly conflicting conditions.

Applying the `all`

function twice to a matrix, as in `all(all(A))`

, always reduces it to a scalar condition.

**See Also**

`any`

, logical operators, relational operators, `colon`

Other functions that collapse an array's dimensions include:

`max`

, `mean`

, `median`

, `min`

, `prod`

, `std`

, `sum`

, `trapz`

alim | allchild |