MATLAB Function Reference |

Determine if all array elements are nonzero

**Syntax**

**Description**

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

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

(`true`

).

If `A`

is a vector, `all(A)`

returns logical `1`

(`true`

) if all the elements are nonzero and returns logical `0`

(`false`

) 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 logical `1`

's and `0`

's.

If `A`

is a multidimensional array, `all(A)`

treats the values along the first nonsingleton 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 `1`

(`true`

) 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 (elementwise and short-circuit), relational operators, `colon`

Other functions that collapse an array's dimensions include `max`

, `mean`

, `median`

, `min`

, `prod`

, `std`

, `sum`

, and `trapz`

.

alim | allchild |

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