# Value of e

**URL:** <https://discourse.julialang.org/t/value-of-e/15958>\
**Category:** General Usage\
**Tags:** question\
**Created:** [October 6, 2018, 5:58am UTC](https://discourse.julialang.org/t/value-of-e/15958 "2018-10-06T05:58:20Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Ajaychat3](https://avatars.discourse-cdn.com/v4/letter/a/ecd19e/32.png) [@Ajaychat3](https://discourse.julialang.org/u/Ajaychat3)\
**Post date:** [October 6, 2018, 5:58am UTC](https://discourse.julialang.org/t/value-of-e/15958/1 "2018-10-06T05:58:20Z")

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how to get around this?

```julia
julia 1.0> e
ERROR: UndefVarError: e not defined

julia 1.0> pi
π = 3.1415926535897...

julia 1.0> golden
ERROR: UndefVarError: golden not defined

```

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<div class="post-metadata">

**Author:** ![Ajaychat3](https://avatars.discourse-cdn.com/v4/letter/a/ecd19e/32.png) [@Ajaychat3](https://discourse.julialang.org/u/Ajaychat3)\
**Post date:** [October 6, 2018, 6:01am UTC](https://discourse.julialang.org/t/value-of-e/15958/2 "2018-10-06T06:01:01Z")

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I got around this. I think I need to use

```julia
\euler+Tab
or
MathConstants.e

```

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**Author:** ![Sukera](https://avatars.discourse-cdn.com/v4/letter/s/ce7236/32.png) [@Sukera](https://discourse.julialang.org/u/Sukera)\
**Post date:** [October 6, 2018, 7:43am UTC](https://discourse.julialang.org/t/value-of-e/15958/3 "2018-10-06T07:43:47Z")

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Those math constants used to be available straight away in 0.6 and have moved to another package in 1.0. If you want to get used to that change and the other changes introduced, use 0.7 until you’re comfortable with the new bindings. 0.7 exists to provide deprecation warnings for stuff that’s moved out of Base in 1.0.

> [@PSA: use Julia 0.7 if you are upgrading](https://discourse.julialang.org/t/psa-use-julia-0-7-if-you-are-upgrading/13321):
>
> A lot of people are posting issues where their old code doesn’t work anymore on 1.0 because some function has been renamed or removed. The 0.7 release exists exactly for this reason: your old code will work on 0.7 and give you a specific warning about how to fix your code. If you have any old code, you should use 0.7 to get these warnings before switching to 1.0; even if you just have work habits that may need changing, you should probably use 0.7 for a while. If someone posts an issue like thi…

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<div class="post-metadata">

**Author:** ![Ajaychat3](https://avatars.discourse-cdn.com/v4/letter/a/ecd19e/32.png) [@Ajaychat3](https://discourse.julialang.org/u/Ajaychat3)\
**Post date:** [October 6, 2018, 2:43pm UTC](https://discourse.julialang.org/t/value-of-e/15958/4 "2018-10-06T14:43:19Z")

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This is a good piece of advice for everyone struggling to migrate old code to Julia 1.0 or trying to learn Julia by running pieces of code available on the net most of which are yet to be updated or replaced. The whole Julia team has done an excellent job by having Julia 0.7 to help an easy migration of old Julia code.

Many thanks to Julia development team.