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How to get the PATH environment-variable separator in Python?
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If, like me, you didn't read the body of this question and just went by the title, you'll think this is the character that separates elements of a filesystem path (forward slash on Linux and MacOSX, backslash on Windows). It's not, it the character...
Create a File object in memory from a string in Java
...tion. I should add that the String data don't exist in a file (so I cannot read my data from a file).
5 Answers
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Is a Java string really immutable?
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As this topic seems overwhelmingly popular, here's some suggested further reading: Heinz Kabutz's Reflection Madness talk from JavaZone 2009, which covers a lot of the issues in the OP, along with other reflection... well... madness.
It covers why this is sometimes useful. And why, most of the ti...
How to base64 encode image in linux bash / shell
...ilename itself.
test="$(cat DSC_0251.JPG | base64)"
However, base64 can read from the file itself:
test=$( base64 DSC_0251.JPG )
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What are metaclasses in Python?
...the object class Foo. If it doesn't, it will use
type to create the class.
Read that several times.
When you do:
class Foo(Bar):
pass
Python does the following:
Is there a __metaclass__ attribute in Foo?
If yes, create in-memory a class object (I said a class object, stay with me here), with th...
Why can a class not be defined as protected?
... package-private which is similar to defining it as default which we can already do.
Therefore there is no benefit of defining a class private it will only make things ambiguous.
For more information read Why an outer Java class can’t be private or protected
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How do I check if a given string is a legal/valid file name under Windows?
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I read the same article mentioned in this answer and found through experimentation that COM0 and LPT0 are also not allowed. @dlf this one works with filenames that begin with '.': ^(?!^(?:PRN|AUX|CLOCK\$|NUL|CON|COM\d|LPT\d)(?...
Hashset vs Treeset
...sal.
None of these implementations are synchronized. That is if multiple threads access a set concurrently, and at least one of the threads modifies the set, it must be synchronized externally.
LinkedHashSet is in some sense intermediate between HashSet and TreeSet. Implemented as a hash table with ...
.NET - Dictionary locking vs. ConcurrentDictionary
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A thread-safe collection vs. a non-threadsafe-collection can be looked upon in a different way.
Consider a store with no clerk, except at checkout. You have a ton of problems if people don't act responsibly. For instance, let's ...
How do I create a list of random numbers without duplicates?
..., 10)
With reference to your specific code example, you probably want to read all the lines from the file once and then select random lines from the saved list in memory. For example:
all_lines = f1.readlines()
for i in range(50):
lines = random.sample(all_lines, 40)
This way, you only need...