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Instance variables vs. class variables in Python
...else it's code created by an aberrant programmer wanting to show off they know some obscure corner of Python programming.
Alex mentions in his reply that access will be (a little bit) faster due to one less level of lookup... let me further clarify for those who don't know about how this works yet....
How to convert PascalCase to pascal_case?
If I had:
31 Answers
31
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If table exists drop table then create it, if it does not exist just create it
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Just put DROP TABLE IF EXISTS `tablename`; before your CREATE TABLE statement.
That statement drops the table if it exists but will not throw an error if it does not.
s...
理解Python的 with 语句 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...ese are useful in exception handling. Let’s see how this works by modifying the above example.
正如你看到的， 1. __enter__()方法被执行 2. __enter__()方法返回的值 - 这个例子中是"Foo"，赋值给变量'sample' 3. 执行代码块，打印变量"sample"的值为 "Foo" 4. _...
How to convert a set to a list in python?
...to a list. You can use the newly built list like any normal list in python now.
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pretty-print JSON using JavaScript
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Pretty-printing is implemented natively in JSON.stringify(). The third argument enables pretty printing and sets the spacing to use:
var str = JSON.stringify(obj, null, 2); // spacing level = 2
If you need syntax highlighting, you might use some regex magic like so:
function...
What is the difference between map and flatMap and a good use case for each?
...ct
res0: Array[String] = Array("Roses are red", "Violets are blue")
Now, map transforms an RDD of length N into another RDD of length N.
For example, it maps from two lines into two line-lengths:
rdd.map(_.length).collect
res1: Array[Int] = Array(13, 16)
But flatMap (loosely speaking...
What is an idiomatic way of representing enums in Go?
...return a.C
}
Inside the main package a.Baser is effectively like an enum now.
Only inside the a package you may define new instances.
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Can I set max_retries for requests.request?
...et the max_retries parameter on the HTTPAdapter() class was added, so that now you have to use alternative transport adapters, see above. The monkey-patch approach no longer works, unless you also patch the HTTPAdapter.__init__() defaults (very much not recommended).
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Explicitly select items from a list or tuple
...ilt-in, but you can make a subclass of list that takes tuples as "indexes" if you'd like:
class MyList(list):
def __getitem__(self, index):
if isinstance(index, tuple):
return [self[i] for i in index]
return super(MyList, self).__getitem__(index)
seq = MyList("foo...