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gersond0001
gersond0001
February 4, 2022
Solved

What is the "context" parameter in reduce()

  • February 4, 2022
  • 2 replies
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Can someone explain with an example the reduce( function, initial, list, context ) function's "context " parameter. I didn't find an example for it in the docs.

Best answer by harshitb6843

Hi there,

I tried implementing various cases of it below for my understanding. 

If we examine the pattern below, it looks like the context is being passed in every evaluation as an extra value along with the initial and respective item from the list. 
Ex. In the expression on line 4, you can see that the result has been increased by 3. This means that the value in 'context' was passed in the function along with the other 2 values, every time the reduce did an iteration. You can find a similar pattern in other expressions written in the above image. 

2 replies

harshitb6843
harshitb6843Answer
February 4, 2022

Hi there,

I tried implementing various cases of it below for my understanding. 

If we examine the pattern below, it looks like the context is being passed in every evaluation as an extra value along with the initial and respective item from the list. 
Ex. In the expression on line 4, you can see that the result has been increased by 3. This means that the value in 'context' was passed in the function along with the other 2 values, every time the reduce did an iteration. You can find a similar pattern in other expressions written in the above image. 

    stefanhelzle0001
    stefanhelzle0001
    Brainy
    February 4, 2022

    The documentation has to say: "Variable number of parameters passed directly into each function evaluation." I think this is pretty clear.

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