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Using python “with” statement with try-except block
...ated operation, in most cases the IOError should abort the whole operation and so be handled at an outer level. Using with statements, you can get rid of all these try...finally statements at inner levels.
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How to add 10 days to current time in Rails
...ven
10.days.from_now
Both definitely work. Are you sure you're in Rails and not just Ruby?
If you definitely are in Rails, where are you trying to run this from? Note that Active Support has to be loaded.
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Class constants in python
...ternatively, you could create intermediate classes: HugeAnimal, BigAnimal, and so on. That would be especially helpful if each animal class will contain different logic.
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Is it possible to declare two variables of different types in a for loop?
...se a structured binding declaration. The syntax has been supported in gcc and clang for years (since gcc-7 and clang-4.0) (clang live example). This allows us to unpack a tuple like so:
for (auto [i, f, s] = std::tuple{1, 1.0, std::string{"ab"}}; i < N; ++i, f += 1.5) {
// ...
}
The above...
App Inventor 2 数学代码块 · App Inventor 2 中文网
...+ )
减 ( - )
乘 ( * )
除 ( / )
幂运算 ( ^ )
随机整数 (random integer)
随机小数 (random fraction)
设定随机数种子 (random set seed to)
最小值 (min)
最大值 (max)
平方根 (square root)
绝对值 (abs)
相反数 (neg)
对数 (log)
e^
四舍五入...
How to remove text from a string?
...123".replace(/data-/g,'');
PS: The replace function returns a new string and leaves the original string unchanged, so use the function return value after the replace() call.
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How to find the php.ini file used by the command line?
...d to enable pdo_mysql in my EasyPhp environment, so I went to php.ini file and uncommented the following line:
14 Answers
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How can I send an email by Java application using GMail, Yahoo, or Hotmail?
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First download the JavaMail API and make sure the relevant jar files are in your classpath.
Here's a full working example using GMail.
import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
public class Main {
private static String U...
What is the difference between :first-child and :first-of-type?
I can't tell the difference between element:first-child and element:first-of-type
3 Answers
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Python xml ElementTree from a string source?
... The problem is that ElementTree.fromstring generates an element, and not an ElementTree! Anyone knows how to work around this?
– Samuel Lampa
Nov 16 '12 at 17:13
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