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How to dynamically build a JSON object with Python?
...and I'm intentionally using this to demonstrate how you can store null and convert it to json null)
import json
print('serialization')
myDictObj = { "name":"John", "age":30, "car":None }
##convert object to json
serialized= json.dumps(myDictObj, sort_keys=True, indent=3)
print(serialized)
## now we...
Can I call a base class's virtual function if I'm overriding it?
Say I have classes Foo and Bar set up like this:
7 Answers
7
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ViewParam vs @ManagedProperty(value = “#{param.id}”)
... could use <f:viewAction> for that instead.
Allows for nested <f:converter> and <f:validator> for more fine-grained conversion/validation. Even a <h:message> can be attached.
Can be included as GET query string using includeViewParams attribute of <h:link> or includeV...
MIT官方已升级至2.70版本，中文网待测试并升级相关特性 - App Inventor 2 ...
2.70 版本主要更新内容：
Features:Add a Japanese translationUpdate the Spanish translationMake the Sharing component respect DefaultFileScope when sharing relative path files (@arjuninv)Add TextChange event, MoveCursor methods, and HintColor property to TextBox and related components (@gordo...
Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABL...
运行故障：edu.mit.appinventor aicompanion3: Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent. Strongly consider using FLAG IMMUTABLE, only use FLAG_MUTABLE if some functionality depends on the PendingIntent being ...
Call to ‘set-and-coerce-property!’ has too few arguments (3; must be...
编译apk，报错：Call to ‘set-and-coerce-property!’ has too few arguments (3; must be 4)
原因是因为代码块有问题/报错，有空的地方没有填值，比如这种：
参考：https://community.appinventor.mi ... 3-must-be-4/20690/4
又学习到了新bug的解决方法...
Service and Characteristic are not published by the connected device -...
Service and Characteristic are not published by the connected device，报错如下：
问题原因：硬件/蓝牙芯片问题导致的，比如A硬件测试好的，换了B硬件没有修改uuid，就出现这个报错。
由于B硬件没有发布这些特征，就会报这个错误。
Why use double indirection? or Why use pointers to pointers?
...
Yes, and if you ever lose track of one of your pointers, here's a pointer: pointerpointer.com
– Andrew Cheong
Aug 21 at 0:50
...
How do I sort a vector of pairs based on the second element of the pair?
...to your question, here's some thoughts ...
if you really wanna be creative and be able to reuse this concept a lot, just make a template:
template <class T1, class T2, class Pred = std::less<T2> >
struct sort_pair_second {
bool operator()(const std::pair<T1,T2>&left, const...
How do I determine the size of my array in C?
...ith the type, like this:
int a[17];
size_t n = sizeof(a) / sizeof(int);
and get the proper answer (68 / 4 = 17), but if the type of
a changed you would have a nasty bug if you forgot to change
the sizeof(int) as well.
So the preferred divisor is sizeof(a[0]) or the equivalent sizeof(*a), the siz...