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Extract subset of key-value pairs from Python dictionary object?
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If you're using Python 3, and you only want keys in the new dict that actually exist in the original one, you can use the fact to view objects implement some set operations:
{k: bigdict[k] for k in bigdict.keys() & {'l', 'm', 'n'}}
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How ViewBag in ASP.NET MVC works
... properties such as ViewBag.Foo and magic strings ViewBag["Hello"] actually work?
7 Answers
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Which is the preferred way to concatenate a string in Python?
...b):
0.0132720470428
a.join(a):
0.114929914474
Well, append/join is marginally faster there if you are using extremely long strings (which you usually aren't, what would you have a string that's 100MB in memory?)
But the real clincher is Python 2.3. Where I won't even show you the timings, because...
Reading header data in Ruby on Rails
..."Cookie"]
New way:
request.headers["HTTP_COOKIE"]
To get a Hash with all headers of the request.
request.headers
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Remove duplicate entries using a Bash script [duplicate]
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Perl one-liner similar to @kev's awk solution:
perl -ne 'print if ! $a{$_}++' input
This variation removes trailing whitespace before comparing:
perl -lne 's/\s*$//; print if ! $a{$_}++' input
This variation edits the file in-place:
perl -i -ne 'print if ! $a{$_}++' input
This variation e...
Differences between “BEGIN RSA PRIVATE KEY” and “BEGIN PRIVATE KEY”
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Copying the content from the above link for quick reference:
#define PEM_STRING_X509_OLD "X509 CERTIFICATE"
#define PEM_STRING_X509 "CERTIFICATE"
#define PEM_STRING_X509_PAIR "CERTIFICATE PAIR"
#define PEM_STRING_X509_TRUSTED "TRUSTED CERTIFICATE"
#define PEM_STRING_X509_REQ_OLD "NEW CERTI...
CORS - How do 'preflight' an httprequest?
...t involves configuring the server responses to include the "Access-Control-Allow-Origin" header and 'preflight' requests with and OPTIONS request. I got the idea from this post : Getting CORS working
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What does @: (at symbol colon) mean in a Makefile?
...nd nothing gets done.
For example (from Linux's scripts/Makefile.clean):
__clean: $(subdir-ymn)
ifneq ($(strip $(__clean-files)),)
+$(call cmd,clean)
endif
ifneq ($(strip $(__clean-dirs)),)
+$(call cmd,cleandir)
endif
ifneq ($(strip $(clean-rule)),)
+$(clean-rule)
endif
@:
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Is it possible to decompile a compiled .pyc file into a .py file?
... .pyc bytecode into .py, whereas unpyclib crashed with an exception.
With all these tools, you get your code back including variable names, but without the comments.
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App Inventor 2 向心力实验App - 手机传感器探究向心力F与角速度ω、半径r...
...* ax + ay * ay)
// 计算向心力 F = m * a
var m = 文本输入框_质量.Text + 0
var r = 文本输入框_半径.Text + 0
global 向心力 = m * 向心加速度
标签_加速度.Text = join("加速度: ", 向心加速度, " m/s²")
标签_角速度.Text = join("角速度: ", 当...