Why is .index faster than .all?

Why is .index faster than .all?

References

Reference NO 1

http://stackoverflow.com/questions/15191123/why-is-index-faster-than-all

Reference NO 2

http://stackoverflow.com/questions/4650848/why-is-model-collection-find-to-a-more-than-10x-faster-than-model-all-in-mon

Reference NO 3

http://stackoverflow.com/questions/2059912/using-an-index-to-recursively-get-all-files-in-a-directory-really-fast

Reference NO 4

http://stackoverflow.com/questions/7632963/numpy-array-how-to-find-index-of-first-occurrence-of-item

Reference NO 5

http://stackoverflow.com/questions/9221312/jquery-get-all-tds-in-a-table-except-those-in-the-first-two-columns

Reference NO 6

#EANF#

Reference NO 7

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Reference NO 8

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