# Pluto show\_image course Computational Thinking

**URL:** <https://discourse.julialang.org/t/pluto-show-image-course-computational-thinking/62728>\
**Category:** New to Julia\
**Tags:** pluto\
**Created:** [June 11, 2021, 10:40am UTC](https://discourse.julialang.org/t/pluto-show-image-course-computational-thinking/62728 "2021-06-11T10:40:32Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![adcsilva](https://avatars.discourse-cdn.com/v4/letter/a/a88e4f/32.png) [@adcsilva](https://discourse.julialang.org/u/adcsilva)\
**Post date:** [June 11, 2021, 10:40am UTC](https://discourse.julialang.org/t/pluto-show-image-course-computational-thinking/62728/1 "2021-06-11T10:40:32Z")

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I am following the lectures of the course Computational Thinking, MIT 18.S191. I would like to run the function `show_image()` used extensively in class 8. The course provides a Pluto notebook [here](https://computationalthinking.mit.edu/Spring21/pca/).

I create a new Pluto notebook to follow the lecture. I run the first block with the setup provided by the notebook in the link above. The setupt adds several packages. However, when I try to execute `show_image()` , I receive the message `UndefVarError: show_image not defined`.

On the other hand, when I simply run the entire notebook provided by the course, the function `show_image()` runs. In principle, running the setup block as I do above would allow the execution of this function. However, when I include myself this block in a new notebook, it does not work. How can I solve this problem?

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**Author:** ![dpsanders](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/dpsanders/32/3573_2.png) [@dpsanders](https://discourse.julialang.org/u/dpsanders)\
**Post date:** [June 11, 2021, 11:03am UTC](https://discourse.julialang.org/t/pluto-show-image-course-computational-thinking/62728/2 "2021-06-11T11:03:08Z")

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The function is defined in a cell at the end of the notebook. Pluto allows you to define cells in any order; it works out the order in which they should be run.

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<div class="post-metadata">

**Author:** ![adcsilva](https://avatars.discourse-cdn.com/v4/letter/a/a88e4f/32.png) [@adcsilva](https://discourse.julialang.org/u/adcsilva)\
**Post date:** [June 11, 2021, 11:09am UTC](https://discourse.julialang.org/t/pluto-show-image-course-computational-thinking/62728/3 "2021-06-11T11:09:33Z")

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This is great! Thank you. I saw in the Appendix. I have just run the cell with the definition of the function in the new notebook and it works fine. I am following your class 8. I teach a course with Matlab (for Economics) and I want to incorporate Julia. Congratulations for your course! Best