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Split data frame string column into multiple columns
... stringr::str_split_fixed
library(stringr)
str_split_fixed(before$type, "_and_", 2)
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Reference — What does this symbol mean in PHP?
This is a collection of questions that come up every now and then about syntax in PHP. This is also a Community Wiki, so everyone is invited to participate in maintaining this list.
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Why is the order in dictionaries and sets arbitrary?
I don't understand how looping over a dictionary or set in python is done by 'arbitrary' order.
6 Answers
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Extracting bits with a single multiplication
I saw an interesting technique used in an answer to another question , and would like to understand it a little better.
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Can someone give an example of cosine similarity, in a very simple, graphical way?
... want to know how similar these texts are, purely in terms of word counts (and ignoring word order). We begin by making a list of the words from both texts:
me Julie loves Linda than more likes Jane
Now we count the number of times each of these words appears in each text:
me 2 2
Jane ...
What is “entropy and information gain”?
I am reading this book ( NLTK ) and it is confusing. Entropy is defined as :
7 Answers
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Speed up the loop operation in R
... over a data.frame object. It simply adds a new column to a data.frame and accumulates something. (simple operation). The data.frame has roughly 850K rows. My PC is still working (about 10h now) and I have no idea about the runtime.
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How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators dif
What is the difference between == and === in PHP?
11 Answers
11
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What does the “yield” keyword do?
What is the use of the yield keyword in Python, and what does it do?
42 Answers
42
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Floating point vs integer calculations on modern hardware
I am doing some performance critical work in C++, and we are currently using integer calculations for problems that are inherently floating point because "its faster". This causes a whole lot of annoying problems and adds a lot of annoying code.
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