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What does “dereferencing” a pointer mean?
... (C++ only) direct or indirect member variables of static objects or their bases, or undergo zero initialisation (e.g. new T(); and new T(x, y, z); perform zero-initialisation on T's members including pointers, whereas new T; does not).
Further, when you assign 0, NULL and nullptr to a pointer the ...
Divide a number by 3 without using *, /, +, -, % operators
...3 + a/1000*3 + (..). In binary it's almost the same: 1 / 3 = 0.0101010101 (base 2), which leads to a / 3 = a/4 + a/16 + a/64 + (..). Dividing by 4 is where the bit shift comes from. The last check on num==3 is needed because we've only got integers to work with.
– Yorick Sijsli...
How to convert an array of strings to an array of floats in numpy?
...port numpy as np
a = ["1.1", "2.2", "3.2"]
b = np.asarray(a, dtype=np.float64, order='C')
For Python 2*:
print a, type(a), type(a[0])
print b, type(b), type(b[0])
resulting in:
['1.1', '2.2', '3.2'] <type 'list'> <type 'str'>
[1.1 2.2 3.2] <type 'numpy.ndarray'> <type 'num...
Applying a git post-commit hook to all current and future repos
... for help, clarification, or responding to other answers.Making statements based on opinion; back them up with references or personal experience.To learn more, see our tips on writing great answers.
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Efficient way to apply multiple filters to pandas DataFrame or Series
...
e can also select rows based on values of a column that are not in a list or any iterable. We will create boolean variable just like before, but now we will negate the boolean variable by placing ~ in the front.
For example
list = [1, 0]
df[df.c...
What is a bus error?
...nd of the allocated object.
Unaligned stack memory accesses in ARMv8 aarch64
This was mentioned at: What is a bus error? for SPARC, but here I will provide a more reproducible example.
All you need is a freestanding aarch64 program:
.global _start
_start:
asm_main_after_prologue:
/* misalign...
Where does PostgreSQL store the database?
Where are the files for a PostgreSQL database stored?
13 Answers
13
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Formula px to dp, dp to px android
...
Note: The widely used solution above is based on displayMetrics.density. However, the docs explain that this value is a rounded value, used with the screen 'buckets'. Eg. on my Nexus 10 it returns 2, where the real value would be 298dpi (real) / 160dpi (default) =...
What does “#define _GNU_SOURCE” imply?
Today I had to use the basename() function, and the man 3 basename ( here ) gave me some strange message:
4 Answers
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Is “double hashing” a password less secure than just hashing it once?
...ions, but the idea is the same. Bcrypt also goes a step beyond most PBKDF2-based solutions by using the derived key to encrypt a well-known plain text. The resulting cipher text is stored as the "hash," along with some meta-data. However, nothing stops you from doing the same thing with PBKDF2.
Her...