大约有 12,000 项符合查询结果（耗时：0.0362秒） [XML]
The easiest way to transform collection to array?
Suppose we have a Collection<Foo> . What is the best (shortest in LoC in current context) way to transform it to Foo[] ? Any well-known libraries are allowed.
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How do you perform a left outer join using linq extension methods
...
For a (left outer) join of a table Bar with a table Foo on Foo.Foo_Id = Bar.Foo_Id in lambda notation:
var qry = Foo.GroupJoin(
Bar,
foo => foo.Foo_Id,
bar => bar.Foo_Id,
(x,y) => new { Foo = x, Bars = y })
.SelectMany(...
When to use dynamic vs. static libraries
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Creating a static library
$$:~/static [32]> cat foo.c
#include<stdio.h>
void foo()
{
printf("\nhello world\n");
}
$$:~/static [33]> cat foo.h
#ifndef _H_FOO_H
#define _H_FOO_H
void foo();
#endif
$$:~/static [34]> cat foo2.c
#include<stdio.h>
void foo2()...
How to trim whitespace from a Bash variable?
...ine a variable containing leading, trailing, and intermediate whitespace:
FOO=' test test test '
echo -e "FOO='${FOO}'"
# > FOO=' test test test '
echo -e "length(FOO)==${#FOO}"
# > length(FOO)==16
How to remove all whitespace (denoted by [:space:] in tr):
FOO=' test test test '
FOO_NO_W...
What is an efficient way to implement a singleton pattern in Java? [closed]
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Use an enum:
public enum Foo {
INSTANCE;
}
Joshua Bloch explained this approach in his Effective Java Reloaded talk at Google I/O 2008: link to video. Also see slides 30-32 of his presentation (effective_java_reloaded.pdf):
The Right Way to...
Split column at delimiter in data frame [duplicate]
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I added a "x|y" line to avoid ambiguities:
df <- data.frame(ID=11:13, FOO=c('a|b','b|c','x|y'))
foo <- data.frame(do.call('rbind', strsplit(as.character(df$FOO),'|',fixed=TRUE)))
Or, if you want to replace the columns in the existing data.frame:
within(df, FOO<-data.frame(do.call('rbin...
How to import a Python class that is in a directory above?
...e to OP's question.
Python is a modular system
This is why we write import foo to load a module "foo" from the root namespace, instead of writing:
foo = dict(); # please avoid doing this
with open(os.path.join(os.path.dirname(__file__), '../foo.py') as foo_fh: # please avoid doing this
exec(co...
How to force 'cp' to overwrite directory instead of creating another one inside?
...Bash script that will overwrite an existing directory. I have a directory foo/ and I am trying to overwrite bar/ with it. But when I do this:
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How to iterate through two lists in parallel?
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Python 3
for f, b in zip(foo, bar):
print(f, b)
zip stops when the shorter of foo or bar stops.
In Python 3, zip
returns an iterator of tuples, like itertools.izip in Python2. To get a list
of tuples, use list(zip(foo, bar)). And to zip until...
When should Flask.g be used?
...print('in app context, before first request context')
print('setting g.foo to abc')
g.foo = 'abc'
print('g.foo should be abc, is: {0}'.format(g.foo))
with app.test_request_context():
print('in first request context')
print('g.foo should be abc, is: {0}'.format(g.foo)...