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How to crop an image in OpenCV using Python

How can I crop images, like I've done before in PIL, using OpenCV. Working example on PIL im = Image. ... please explain how I can correctly use this function. Question&Answers:os...

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

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reactjs - Uncaught Error: Invariant Violation: Element type is invalid: expected a string (for built-in components) or a class/function but got: object

I am getting this error: Uncaught Error: Invariant Violation: Element type is invalid: expected a string (for built-in ... ); }, }); module.exports = Home; 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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How do I see if Wi-Fi is connected on Android?

I don't want my user to even try downloading something unless they have Wi-Fi connected. However, I can ... , I am getting OBTAINING_IPADDR as the state. Question&Answers:os...

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

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207 views

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Get selected value of a dropdown's item using jQuery

How can I get the selected value of a dropdown box using jQuery? I tried using var value = $('#dropDownId').val() ... ').val(); but both return an empty string. Question&Answers:os...

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

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.net - How do you simulate Mouse Click in C#?

How do you simulate Mouse clicks in C# winforms applications? Question&Answers:os...

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

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python - Why does this iterative list-growing code give IndexError: list assignment index out of range?

Please consider the following code: i = [1, 2, 3, 5, 8, 13] j = [] k = 0 for l in i: j[k] ... 's something simple I don't understand. Can someone clear it up? Question&Answers:os...

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

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Firing a Keyboard Event in Safari, using JavaScript

I'm trying to simulate a keyboard event in Safari using JavaScript. I have tried this: var event = document. ... to achieve it in plain JavaScript if possible.) Question&Answers:os...

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

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priority queue - The built-in iterator for java's PriorityQueue does not traverse the data structure in any particular order. Why?

This is straight from the Java Docs: This class and its iterator implement all of the optional methods of ... traverse the PriorityQueue in its natural order? Question&Answers:os...

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

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How can one change the timestamp of an old commit in Git?

The answers to How to modify existing, unpushed commits? describe a way to amend previous commit messages that haven't yet ... a way to also re-set the times? Question&Answers:os...

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

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c++ - usr/bin/ld: cannot find -l<nameOfTheLibrary>

I'm trying to compile my program and it returns this error : usr/bin/ld: cannot find -l<nameOfTheLibrary> in my ... an option to add to make it work please? Question&Answers:os...

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

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string - endsWith in JavaScript

How can I check if a string ends with a particular character in JavaScript? Example: I have a string var str = " ... the best way or there is any other way? Question&Answers:os...

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

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networking - Detect network connection type on Android

How do you detect the network connection type on Android? Is it through ConnectivityManager.getActiveNetworkInfo(). ... answer limited to Wifi and mobile? Question&Answers:os...

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

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369 views

1 answer

linux - mysql_config not found when installing mysqldb python interface

I am trying to get a Python script to run on the linux server I'm connected to via ssh. The script uses ... it/what can I do to successfully install mysqldb? Question&Answers:os...

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

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How to return dictionary keys as a list in Python?

In Python 2.7, I could get dictionary keys, values, or items as a list: >>> newdict = {1:0, 2:0, 3:0} > ... is there a better way to return a list in Python 3? Question&Answers:os...

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

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r - Show percent % instead of counts in charts of categorical variables

I'm plotting a categorical variable and instead of showing the counts for each category value. I'm looking ... googling for that error gives a single result. Question&Answers:os...

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

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Ruby ampersand colon shortcut

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

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176 views

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sql - Inner join vs Where

Is there a difference in performance (in oracle) between Select * from Table1 T1 Inner Join Table2 T2 On T1.ID = T2.ID ... T1, Table2 T2 Where T1.ID = T2.ID ? Question&Answers:os...

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

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140 views

1 answer

How can I get the external SD card path for Android 4.0+?

Samsung Galaxy S3 has an external SD card slot, which is mounted to /mnt/extSdCard. How can I get this path ... . (Or removable USB storage on some tablets.) Question&Answers:os...

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

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191 views

1 answer

c# - Do event handlers stop garbage collection from occurring?

If I have the following code: MyClass pClass = new MyClass(); pClass.MyEvent += MyFunction; pClass = null; ... ; pClass.MyEvent -= MyFunction; pClass = null; Question&Answers:os...

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

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98 views

1 answer

Python JSON serialize a Decimal object

I have a Decimal('3.9') as part of an object, and wish to encode this to a JSON string which should look ... is wrong, and will be a big waste of bandwidth. Question&Answers:os...

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

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63 views

1 answer

c++ - How can I pass a class member function as a callback?

I'm using an API that requires me to pass a function pointer as a callback. I'm trying to use this API ... explanation for this?? I'm using VS2008. Thanks!! Question&Answers:os...

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

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170 views

1 answer

r - Add ID column by group

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

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366 views

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Is it possible to use karate 'match' inside conditional statement?

Find the example here. def a = condition ? " karate match statement " : "karate match statement" Is it possible to do something like this?? Question&Answers:os...

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

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239 views

1 answer

python - How can i shoot a bullet with space bar?

Heres my code import pygame, os os.environ["SDL_VIDEO_CENTERED"] = "1" pygame.init() win = pygame.display d = ... once, it breaks the while self.shooting loop. Question&Answers:os...

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

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79 views

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python - What is the difference between pip and conda?

I know pip is a package manager for python packages. However, I saw the installation on IPython's website use ... What is the difference between pip and conda? Question&Answers:os...

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

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343 views

1 answer

scala - Task not serializable: java.io.NotSerializableException when calling function outside closure only on classes not objects

Getting strange behavior when calling function outside of a closure: when function is in a object everything is working when ... def someFunc(a:Int) = a+1 } Question&Answers:os...

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

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414 views

1 answer

c - How to make child process die after parent exits?

Suppose I have a process which spawns exactly one child process. Now when the parent process exits for ... Kill child process when parent process is killed Question&Answers:os...

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

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216 views

1 answer

python - selenium with scrapy for dynamic page

I'm trying to scrape product information from a webpage, using scrapy. My to-be-scraped webpage looks like this ... follows Any idea is appreciated. Thank you! Question&Answers:os...

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

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