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How to remove from a map while iterating it?
... (must_delete)
{
m.erase(it++); // or "it = m.erase(it)" since C++11
}
else
{
++it;
}
}
Note that we really want an ordinary for loop here, since we are modifying the container itself. The range-based loop should be strictly reserved for situations where we only care about the...
How can I add or update a query string parameter?
...])" + key + "=.*?(&|$)", "i");
var separator = uri.indexOf('?') !== -1 ? "&" : "?";
if (uri.match(re)) {
return uri.replace(re, '$1' + key + "=" + value + '$2');
}
else {
return uri + separator + key + "=" + value;
}
}
...
Combining two Series into a DataFrame in pandas
I have two Series s1 and s2 with the same (non-consecutive) indices. How do I combine s1 and s2 to being two columns in a DataFrame and keep one of the indices as a third column?
...
How to avoid warning when introducing NAs by coercion
...
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)
...
Remove unwanted parts from strings in a column
...
173
data['result'] = data['result'].map(lambda x: x.lstrip('+-').rstrip('aAbBcC'))
...
Execution failed app:processDebugResources Android Studio
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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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Getting the count of unique values in a column in bash
...
153
To see a frequency count for column two (for example):
awk -F '\t' '{print $2}' * | sort | un...