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Python extending with - using super() Python 3 vs Python 2
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super() (without arguments) was introduced in Python 3 (along with __class__):
super() -> same as super(__class__, self)
so that would be the Python 2 equivalent for new-style classes:
super(CurrentClass, self)
for old-style classes you can always use:
class Classname...
Postgres - FATAL: database files are incompatible with server
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413
If you recently upgraded to 11 or 12 from 10.x you can run the below command to upgrade your pos...
UIView with rounded corners and drop shadow?
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33 Answers
33
Active
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What is float in Java?
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In Java, when you type a decimal number as 3.6, its interpreted as a double. double is a 64-bit precision IEEE 754 floating point, while floatis a 32-bit precision IEEE 754 floating point. As a float is less precise than a double, the conversion cannot be performed i...
Any way to properly pretty-print ordered dictionaries?
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133
As a temporary workaround you can try dumping in JSON format.
You lose some type information, b...
What are all the uses of an underscore in Scala?
...](a: K[T])
Ignored variables
val _ = 5
Ignored parameters
List(1, 2, 3) foreach { _ => println("Hi") }
Ignored names of self types
trait MySeq { _: Seq[_] => }
Wildcard patterns
Some(5) match { case Some(_) => println("Yes") }
Wildcard patterns in interpolations
"abc" match {...
Remove all special characters, punctuation and spaces from string
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378
This can be done without regex:
>>> string = "Special $#! characters spaces 888323...
What is “entropy and information gain”?
...# ------------------------------------------------
Ashley 1 3 6 f
Brian 0 2 5 m
Caroline 1 4 8 f
David 0 2 5 m
The goal is to build a decision tree. An example of a tree ...
App Inventor 2 数学代码块 · App Inventor 2 中文网
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返回第一个数字的第二个数字次幂的结果。比如2^3 = 222 = 8
随机整数 (random integer)
返回给定值之间（包含首尾）的随机整数值。参数的顺序不限，也就是 1~100 和 100~1 效果一样。
随机小数 (random fraction)
返回 0 到 1 ...
Pandas conditional creation of a series/dataframe column
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Set Type color
0 Z A green
1 Z B green
2 X B red
3 Y C red
If you have more than two conditions then use np.select. For example, if you want color to be
yellow when (df['Set'] == 'Z') & (df['Type'] == 'A')
otherwise blue when (df['Set'] == 'Z') & (df[...