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javascript - variable === undefined vs. typeof variable === "undefined"

The jQuery Core Style Guidelines suggest two different ways to check whether a variable is defined. Global ... variables and another for locals and properties? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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javascript - Any difference between await Promise.all() and multiple await?

Is there any difference between: const [result1, result2] = await Promise.all([task1(), task2()]); and const t1 = ... [result1, result2] = [await t1, await t2]; Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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java - SSL and cert keystore

How does my Java program know where my keystore containing the certificate is? Or alternatively: How do I tell ... use for authenticating the server to client? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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stdint - How to print a int64_t type in C

C99 standard has integer types with bytes size like int64_t. I am using Windows's %I64d format currently ( ... print my_int variable without having a warning? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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objective c - Convert NSDate to NSString

How do I convert, NSDate to NSString so that only the year in @"yyyy" format is output to the string? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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javascript - How to get the function name from within that function?

How can I access a function name from inside that function? // parasitic inheritance var ns.parent.child = function() { ... } var obj = new ns.parent.child(); Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - Paging with Oracle

I am not as familiar with Oracle as I would like to be. I have some 250k records, and I want to display ... to integrate in very well with my new stored procs. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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python - Method Resolution Order (MRO) in new-style classes?

In the book Python in a Nutshell (2nd Edition) there is an example which uses old style classes to ... Please help me in better understanding of MRO. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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performance - Is it safe to shallow clone with --depth 1, create commits, and pull updates again?

The --depth 1 option in git clone: Create a shallow clone with a history truncated to the specified number of ... again to keep up with updates from origin? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c# - Will using 'var' affect performance?

Earlier I asked a question about why I see so many examples use the varkeyword and got the answer that while it ... of the code if it was used everywhere? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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c++ - When should std::move be used on a function return value?

This question already has answers here: Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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python - Convert Pandas column containing NaNs to dtype `int`

I read data from a .csv file to a Pandas dataframe as below. For one of the columns, namely id, I want ... Cannot convert NA to integer How can I tackle this? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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php - How to get the jQuery $.ajax error response text?

I am sending an error response to my jQuery. However, I can not get the response text (in the example below this ... alert: Can't do because: error Any ideas? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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javascript - How to get progress from XMLHttpRequest

Is it possible to get the progress of an XMLHttpRequest (bytes uploaded, bytes downloaded)? This would be useful to ... , which the browser has at all times. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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rounding - How to round to 2 decimals with Python?

I am getting a lot of decimals in the output of this code (Fahrenheit to Celsius converter). My code currently ... round every answer to the 2nd decimal place? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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Security of Python's eval() on untrusted strings?

If I am evaluating a Python string using eval(), and have a class like: class Foo(object): a = 3 ... ) without custom dictionaries is unsafe in most cases. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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android - Can not find a View with findViewById()

I cannot find a TextView by calling findViewById(), even though the ID does exist. OtherActivity: public class ... , but why is the variable textView null? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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How to check a not-defined variable in JavaScript

I wanted to check whether the variable is defined or not. For example, the following throws a not-defined error alert( x ); How can I catch this error? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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229 views

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metaclass - class << self idiom in Ruby

What does class << self do in Ruby? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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pip install mysql-python fails with EnvironmentError: mysql_config not found

This is the error I get (mysite)zjm1126@zjm1126-G41MT-S2:~/zjm_test/mysite$ pip install mysql-python Downloading/unpacking ... What can I do to resolve this? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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sql - Oracle: If Table Exists

I'm writing some migration scripts for an Oracle database, and was hoping Oracle had something similar to MySQL's ... that together with a DROP is escaping me. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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exception handling - Python try-else

What is the intended use of the optional else clause of the try statement? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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data structures - JavaScript hashmap equivalent

As made clear in update 3 on this answer, this notation: var hash = {}; hash[X] does ... objects with equivalent string representations overwrite each other. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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php - Getting visitors country from their IP

I want to get visitors country via their IP... Right now I'm using this (http://api.hostip.info/country ... , something like ip2country ready made code and CSV. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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81 views

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android - Percentage width in a RelativeLayout

I am working on a form layout for a Login Activity in my Android App. The image below is how I want it ... android:textSize="18sp" > </Button> </RelativeLayout> Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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168 views

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c# - Can I automatically increment the file build version when using Visual Studio?

I was just wondering how I could automatically increment the build (and version?) of my files using ... www.codeproject.com/KB/dotnet/AutoIncrementVersion.aspx) Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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python - Should you always favor xrange() over range()?

Why or why not? Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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r - How to change facet labels?

I have used the following ggplot command: ggplot(survey, aes(x = age)) + stat_bin(aes(n = nrow(h3), y ... at the facet_grid help page but cannot figure out how. Question&Answers:os...

asked Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

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