# Test on each value of a vector

**URL:** <https://discourse.julialang.org/t/test-on-each-value-of-a-vector/71622>\
**Category:** General Usage\
**Tags:** question\
**Created:** [November 16, 2021, 11:01pm UTC](https://discourse.julialang.org/t/test-on-each-value-of-a-vector/71622 "2021-11-16T23:01:01Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![corny85](https://avatars.discourse-cdn.com/v4/letter/c/a88e4f/32.png) [@corny85](https://discourse.julialang.org/u/corny85)\
**Post date:** [November 16, 2021, 11:01pm UTC](https://discourse.julialang.org/t/test-on-each-value-of-a-vector/71622/1 "2021-11-16T23:01:01Z")

</div>

Hello,

I have a vector D and i want to test if all values are less than 1 or not.  
I’ve tried

```julia
if(D[k]<1 for k=1:size(D,1))
    return true
else
    return false
end

```

but it does not work.

Thanks in advance for your help.

---

<div class="post-metadata">

**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [November 16, 2021, 11:48pm UTC](https://discourse.julialang.org/t/test-on-each-value-of-a-vector/71622/2 "2021-11-16T23:48:33Z")

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`all(<(1), D)` works.

If you want to write an explicit loop, you would want something like:

```julia
for d in D
    if d ≥ 1
        return false
    end
end
return true

```

---

<div class="post-metadata">

**Author:** ![corny85](https://avatars.discourse-cdn.com/v4/letter/c/a88e4f/32.png) [@corny85](https://discourse.julialang.org/u/corny85)\
**Post date:** [November 17, 2021, 11:28am UTC](https://discourse.julialang.org/t/test-on-each-value-of-a-vector/71622/3 "2021-11-17T11:28:40Z")

</div>

Thanks a lot !

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<div class="post-metadata">

**Author:** ![rafael.guerra](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rafael.guerra/32/216610_2.png) [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Post date:** [November 17, 2021, 6:52pm UTC](https://discourse.julialang.org/t/test-on-each-value-of-a-vector/71622/4 "2021-11-17T18:52:26Z")

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> [@stevengj](#):
>
> all(\<(1), D)

Could you please explain/point to doc to better understand how this works?  
And the role of bracketing `(1)`.  
Thank you.

---

<div class="post-metadata">

**Author:** ![lmiq](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/lmiq/32/18314_2.png) [@lmiq](https://discourse.julialang.org/u/lmiq)\
**Post date:** [November 17, 2021, 7:06pm UTC](https://discourse.julialang.org/t/test-on-each-value-of-a-vector/71622/5 "2021-11-17T19:06:53Z")

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The `? all` and `? <()` are pretty clear here 🙂 .

```julia

  <(x)

  Create a function that compares its argument to x using <, i.e. a function
  equivalent to y -> y < x. The returned function is of type
  Base.Fix2{typeof(<)}, which can be used to implement specialized methods.

  │ Julia 1.2
  │
  │ This functionality requires at least Julia 1.2.

```

---

<div class="post-metadata">

**Author:** ![rafael.guerra](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/rafael.guerra/32/216610_2.png) [@rafael.guerra](https://discourse.julialang.org/u/rafael.guerra)\
**Post date:** [November 17, 2021, 7:09pm UTC](https://discourse.julialang.org/t/test-on-each-value-of-a-vector/71622/6 "2021-11-17T19:09:17Z")

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Thank you, as my brain was overheating… 🙂

Julia is very subtle. The first impulse would have been to write something less efficient like:

```julia
all(D .< 1)

```