大约有 16,000 项符合查询结果（耗时：0.0309秒） [XML]
Converting RGB to grayscale/intensity
When converting from RGB to grayscale, it is said that specific weights to channels R, G, and B ought to be applied. These weights are: 0.2989, 0.5870, 0.1140.
...
How to load all modules in a folder?
...reate an empty __init__.py file under Foo/
Execute
import pkgutil
import sys
def load_all_modules_from_dir(dirname):
for importer, package_name, _ in pkgutil.iter_modules([dirname]):
full_package_name = '%s.%s' % (dirname, package_name)
if full_package_name not in sys.modules...
Why do we need C Unions?
...
Unions are often used to convert between the binary representations of integers and floats:
union
{
int i;
float f;
} u;
// Convert floating-point bits to integer:
u.f = 3.14159f;
printf("As integer: %08x\n", u.i);
Although this is technicall...
Cast Double to Integer in Java
...imitives, which makes it possible to use them like objects.
Strategy:
To convert a Double to an Integer you would need to follow this strategy:
Convert the Double object to a primitive double. (= "unboxing")
Convert the primitive double to a primitive int. (= "casting")
Convert the primitive int...
Converting a Date object to a calendar object [duplicate]
...);
date = (Date)formatter.parse(date.toString());
DateFormat is used to convert Strings to Dates (parse()) or Dates to Strings (format()). You are using it to parse the String representation of a Date back to a Date. This can't be right, can it?
...
Convert a string to an enum in C#
What's the best way to convert a string to an enumeration value in C#?
25 Answers
25
...
How do I find the location of my Python site-packages directory?
...r user.
Global site-packages ("dist-packages") directories are listed in sys.path when you run:
python -m site
For a more concise list run getsitepackages from the site module in Python code:
python -c 'import site; print(site.getsitepackages())'
Note: With virtualenvs getsitepackages is not...
Creating hidden arguments with Python argparse
...by adding an option to enable the hidden ones, and grab that by looking at sysv.args.
If you do this, you have to include the special arg you pick out of sys.argv directly in the parse list if you Assume the option is -s to enable hidden options.
parser.add_argument('-a', '-axis',
...
Filter rows which contain a certain string
..., I will add a toy example using the mtcars data set. Imagine you are only interested in cars produced by Mazda or Toyota.
mtcars$type <- rownames(mtcars)
dplyr::filter(mtcars, grepl('Toyota|Mazda', type))
mpg cyl disp hp drat wt qsec vs am gear carb type
1 21.0 6 160.0 110...
How to create a string with format?
I need to create a string with format which can convert int, long, double etc. types into string. Using Obj-C, I can do it via below way.
...