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security - How do you Encrypt and Decrypt a PHP String?

What I mean is: Original String + Salt or Key --> Encrypted String Encrypted String + Salt or Key --> ... use Crypt_Blowfish, but it didn't work for me. Question&Answers:os...

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

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180 views

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java - Initialize class fields in constructor or at declaration?

I've been programming in C# and Java recently and I am curious where the best place is to initialize my class ... to be consistent and stick to one approach. Question&Answers:os...

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

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In JavaScript, does it make a difference if I call a function with parentheses?

I noticed a difference when calling a function with empty parentheses, or without any parentheses at all. However ... ; Please explain the principle behind it. Question&Answers:os...

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

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sql - How do I update if exists, insert if not (AKA "upsert" or "merge") in MySQL?

Is there an easy way to INSERT a row when it does not exist, or to UPDATE if it exists, using one MySQL query? Question&Answers:os...

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

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algorithm - What is the fastest/most efficient way to find the highest set bit (msb) in an integer in C?

If I have some integer n, and I want to know the position of the most significant bit (that is, if the least ... seem like they'd only work on 32 bit ints). Question&Answers:os...

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

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Questions about Java's String pool

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

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c++ - What is a dangling pointer?

I know this is pretty common question, but still new for me! I don't understand concept of dangling pointer, was ... print name or do something with name... } Question&Answers:os...

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

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java - Implementing back/forward buttons in Swing

I have a quick question. I'm getting a little bit of experience with Swing and the easiest way to do ... } // end private inner class TextFieldHandler } Question&Answers:os...

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

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ios - DateFormatter doesn't return date for "HH:mm:ss"

Here is the code excerpt: func mapping(map: Map) { time <- (map["time"], TransformOf<Date, String>(fromJSON: { let ... iPod 10.1.1 (2016). This is so weird. Question&Answers:os...

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

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Clear terminal in Python

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

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MySQL Error 1215: Cannot add foreign key constraint

I am trying to forward engineer my new schema onto my db server, but I can't figure out why I am getting this ... , PRIMARY KEY (`Emp_ID`) ) ENGINE = InnoDB Question&Answers:os...

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

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ruby - Is there any difference between the `:key => "value"` and `key: "value"` hash notations?

Is there any difference between :key => "value" (hashrocket) and key: "value" (Ruby 1.9) notations? If not, then ... me to convert from :x => to x: notations? Question&Answers:os...

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

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CSS - how to overflow from div to full width of screen

I have a containing DIV, that I use as part of my responsive grid. It expands to the maximum width I allow which ... but is it possible to achieve what I want? Question&Answers:os...

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

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mysql - need to return two sets of data with two different where clauses

I have a table that keeps track of transactions. The table is setup as: transactions: id, account_id, budget_id, ... 200000 100 242 100000 5020 621 45000 3940 Question&Answers:os...

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

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algorithm - Why do we check up to the square root of a prime number to determine if it is prime?

To test whether a number is prime or not, why do we have to test whether it is divisible only up to the square root of that number? Question&Answers:os...

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

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200 views

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objective c - OpenCV C++/Obj-C: Detecting a sheet of paper / Square Detection

I successfully implemented the OpenCV square-detection example in my test application, but now need to filter the output, ... // blue } } return image; } Question&Answers:os...

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

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464 views

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clone - Java: recommended solution for deep cloning/copying an instance

I'm wondering if there is a recommended way of doing deep clone/copy of instance in java. I have 3 solutions ... here ? Which one would you recommend ? Thanks. Question&Answers:os...

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

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404 views

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RegEx: Grabbing values between quotation marks

I have a value like this: "Foo Bar" "Another Value" something else What regex will return the values enclosed in the ... marks (e.g. Foo Bar and Another Value)? Question&Answers:os...

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

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328 views

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multithreading - Maximum number of threads per process in Linux?

What is the maximum number of threads that can be created by a process under Linux? How (if possible) can this value be modified? Question&Answers:os...

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

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206 views

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Check if PHP session has already started

I have a PHP file that is sometimes called from a page that has started a session and sometimes from a page ... work properly and just shut up the warnings? Question&Answers:os...

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

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283 views

1 answer

c# - A field initializer cannot reference the nonstatic field, method, or property

I have a class and when I try to use it in another class I receive the error below. using System; using System ... Why does it happen and how to fix it? Question&Answers:os...

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

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257 views

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regex - How can I match a whole word in JavaScript?

I am trying to search a single whole word through a textbox. Say I search "me", I should find all occurrences of ... )/g).test(2)); Moving lines is essential Question&Answers:os...

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

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79 views

1 answer

java - How to get X and Y index of element inside GridLayout?

I am studying a java tutorial and saw that the way to find the x/y indexes of a JButton inside a GridLayout is to ... setVisible(true); g.setSize(500, 500); } } Question&Answers:os...

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

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56 views

1 answer

python - Changing one character in a string

What is the easiest way in Python to replace a character in a string? For example: text = "abcdefg"; text[1] = "Z"; ^ Question&Answers:os...

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

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871 views

1 answer

text formatting - How to output numbers with leading zeros in JavaScript?

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

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927 views

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java - GSON throwing "Expected BEGIN_OBJECT but was BEGIN_ARRAY"?

I'm trying to parse a JSON string like this one [ { "updated_at":"2012-03-02 21:06:01", "fetched_at":"2012-03 ... line 1 column 2 Any ideas how should I fix it? Question&Answers:os...

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

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113 views

1 answer

r - How to split a data frame?

I want to split a data frame into several smaller ones. This looks like a very trivial question, however I cannot find a solution from web search. Question&Answers:os...

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

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88 views

1 answer

How to set a Timer in Java?

How to set a Timer, say for 2 minutes, to try to connect to a Database then throw exception if there is any issue in connection? Question&Answers:os...

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

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