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Python List vs. Array - when to use?
...even for data that could be represented with simple C types (e.g. float or uint64_t).
The array.array type, on the other hand, is just a thin wrapper on C arrays. It can hold only homogeneous data (that is to say, all of the same type) and so it uses only sizeof(one object) * length bytes of memory...
Where do I find the definition of size_t?
...ize of a unsigned int. However we are moving to 64bit addressing while the uint will most likely stay at 32bits (it's size is not guaranteed in the c++ standard). To make your code that depends on the memory size portable across architectures you should use a size_t. For example things like array si...
Convert RGBA PNG to RGB with PIL
...ld_setting)
out[alpha] *= 255
np.clip(out,0,255)
# astype('uint8') maps np.nan (and np.inf) to 0
out = out.astype('uint8')
out = Image.fromarray(out, 'RGBA')
return out
FNAME = 'logo.png'
img = Image.open(FNAME).convert('RGBA')
white = Image.new('RGBA', size ...
MD5 algorithm in Objective-C
... };
char *resultData = malloc(CC_MD5_DIGEST_LENGTH * 2 + 1);
for (uint index = 0; index < CC_MD5_DIGEST_LENGTH; index++) {
resultData[index * 2] = HexEncodeChars[(result[index] >> 4)];
resultData[index * 2 + 1] = HexEncodeChars[(result[index] % 0x10)];
}
res...
Get a pixel from HTML Canvas?
...ray(4) [0, 251, 0, 255]
b = idt.data.subarray(188411*4, 188411*4 + 4) // Uint8ClampedArray(4) [0, 251, 0, 255]
a[0] = 255 // Does nothing
getPixel(idt, 188411), // Array(4) [0, 251, 0, 255]
b[0] = 255 // Mutates the original imgData.data
getPixel(idt, 188411), // Array(4) [255, 251, 0, 255]
// ...
What's the recommended way to connect to MySQL from Go?
...l { /* error handling */}
items := make([]*SomeStruct, 0, 10)
var ida, idb uint
for rows.Next() {
err = rows.Scan(&ida, &idb)
if err != nil { /* error handling */}
items = append(items, &SomeStruct{ida, idb})
}
Insert :
_, err = con.Exec("insert into tbl (id, mdpr, isok) ...
Mapping two integers to one, in a unique and deterministic way
...1;
}
public static int PerfectlyHashThem(short a, short b)
{
var A = (uint)(a >= 0 ? 2 * a : -2 * a - 1);
var B = (uint)(b >= 0 ? 2 * b : -2 * b - 1);
var C = (int)((A >= B ? A * A + A + B : A + B * B) / 2);
return a < 0 && b < 0 || a >= 0 && b >...
Efficient Algorithm for Bit Reversal (from MSB->LSB to LSB->MSB) in C
... $4, %rsi
cmpq $400000000, %rsi
jne .L3
EDIT: I also tried using uint64_t types on my machine to see if there was any performance boost. Performance was about 10% faster than 32-bit, and was nearly identical whether you were just using 64-bit types to reverse bits on two 32-bit int types ...
Assign pandas dataframe column dtypes
...t pandas as pd
import numpy as np
x = np.empty((10,), dtype=[('x', np.uint8), ('y', np.float64)])
df = pd.DataFrame(x)
df.dtypes ->
x uint8
y float64
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Fastest way to check if string contains only digits
... null || s == "") return false; for (int i = 0; i < s.Length; i++) if ((uint)(s[i] - '0') > 9) return false; return true; }
static bool isDigitsFx(string s) { if (s == null || s == "") return false; for (int i = 0; i < s.Length; i++) if ((s[i] ^ '0') > 9) return false; return true; }
sta...