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What is the difference between a static and a non-static initialization code block

...own, just like simple variable initializers) when the class is loaded (actually, when it's resolved, but that's a technicality). Instance initializers are executed in the order defined when the class is instantiated, immediately before the constructor code is executed, immediately after the invocat...
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Hashing a dictionary?

...e hash(): hash(frozenset(my_dict.items())) This is much less computationally intensive than generating the JSON string or representation of the dictionary. UPDATE: Please see the comments below, why this approach might not produce a stable result. ...
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Ora-00257 错误处理一列 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术

... 没有问题 查看权限 ll .bash_profile -rw--rw--- 1 oracle oinstall 529 10鏈?24 20:18 /home/oracle/.bash_profile 有问题。修改权限 chmod 775 /home/oracle/.bash_profile 进入ORLACE sqlplus /as sysdba SQL> select * from v$log; GROUP# THREAD# SEQUE...
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Do try/catch blocks hurt performance when exceptions are not thrown?

... { Console.WriteLine(ex.ToString()); } finally { d = Math.Sin(d); } } w.Stop(); Console.Write(" try/catch/finally: "); Console.WriteLine(w.ElapsedMilliseconds); w.Reset(); d = 0; w.Start(); for (int i = ...
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How to make a chain of function decorators?

...her object scream = shout # Notice we don't use parentheses: we are not calling the function, # we are putting the function "shout" into the variable "scream". # It means you can then call "shout" from "scream": print(scream()) # outputs : 'Yes!' # More than that, it means you can remove the old...
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How do I add a placeholder on a CharField in Django?

... Look at the widgets documentation. Basically it would look like: q = forms.CharField(label='search', widget=forms.TextInput(attrs={'placeholder': 'Search'})) More writing, yes, but the separation allows for better abstraction of more complic...
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How do I run all Python unit tests in a directory?

...it test module is of the form test_*.py . I am attempting to make a file called all_test.py that will, you guessed it, run all files in the aforementioned test form and return the result. I have tried two methods so far; both have failed. I will show the two methods, and I hope someone out there ...
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Store JSON object in data attribute in HTML jQuery

...in the text just use $('#myElement').data('key',jsonObject); it won't actually be stored in the html, but if you're using jquery.data, all that is abstracted anyway. To get the JSON back don't parse it, just call: var getBackMyJSON = $('#myElement').data('key'); If you are getting [Object Objec...
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node.js require all files in a folder?

How do I require all files in a folder in node.js? 14 Answers 14 ...
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What do commas and spaces in multiple classes mean in CSS?

..._12 .grid_6, .container_16 .grid_8 { width: 460px; } That says "make all .grid_6's within .container_12's and all .grid_8's within .container_16's 460 pixels wide." So both of the following will render the same: <div class="container_12"> <div class="grid_6">460px Wide</div&g...