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How to avoid warning when introducing NAs by coercion
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142
Use suppressWarnings():
suppressWarnings(as.numeric(c("1", "2", "X")))
[1] 1 2 NA
This su...
How to compare two dates?
...rt datetime, timedelta
>>> past = datetime.now() - timedelta(days=1)
>>> present = datetime.now()
>>> past < present
True
>>> datetime(3000, 1, 1) < present
False
>>> present - datetime(2000, 4, 4)
datetime.timedelta(4242, 75703, 762105)
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Why are elementwise additions much faster in separate loops than in a combined loop?
Suppose a1 , b1 , c1 , and d1 point to heap memory and my numerical code has the following core loop.
10 Answers
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Remove unwanted parts from strings in a column
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173
data['result'] = data['result'].map(lambda x: x.lstrip('+-').rstrip('aAbBcC'))
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How to COUNT rows within EntityFramework without loading contents?
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124
Query syntax:
var count = (from o in context.MyContainer
where o.ID == '1'
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HashMap get/put complexity
We are used to saying that HashMap get/put operations are O(1). However it depends on the hash implementation. The default object hash is actually the internal address in the JVM heap. Are we sure it is good enough to claim that the get/put are O(1) ?
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Get query string parameters url values with jQuery / Javascript (querystring)
...n use this new API to get values from the location!
// Assuming "?post=1234&action=edit"
var urlParams = new URLSearchParams(window.location.search);
console.log(urlParams.has('post')); // true
console.log(urlParams.get('action')); // "edit"
console.log(urlParams.getAll('action')); // ["ed...
Iterating over a numpy array
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188
I think you're looking for the ndenumerate.
>>> a =numpy.array([[1,2],[3,4],[5,6]])
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Getting the count of unique values in a column in bash
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153
To see a frequency count for column two (for example):
awk -F '\t' '{print $2}' * | sort | un...