大约有 40,000 项符合查询结果（耗时：0.0356秒） [XML]
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...
Looping over arrays, printing both index and value
...., not splitting them on whitespace. If foo=(x 'y z'), then f "${foo[@]}" calls f with two arguments, x and 'y z'. Metadata queries like "${!foo[@]}" and "${#foo[@]}" similarly act on foo as an array.
– BallpointBen
Sep 5 '18 at 1:23
...
What is the difference between char s[] and char *s?
...puts the literal string in read-only memory and copies the string to newly allocated memory on the stack. Thus making
s[0] = 'J';
legal.
share
|
improve this answer
|
foll...
Is there a command to refresh environment variables from the command prompt in Windows?
... environment variables with a vbs script, but you need a bat script to actually change the current environment variables, so this is a combined solution.
Create a file named resetvars.vbs containing this code, and save it on the path:
Set oShell = WScript.CreateObject("WScript.Shell")
filename =...
List changes unexpectedly after assignment. How do I clone or copy it to prevent this?
...
With new_list = my_list, you don't actually have two lists. The assignment just copies the reference to the list, not the actual list, so both new_list and my_list refer to the same list after the assignment.
To actually copy the list, you have various possibilit...
How do you access the matched groups in a JavaScript regular expression?
...not very intuitive. This lead to the proposal of the String.prototype.matchAll method. This new method is expected to ship in the ECMAScript 2020 specification. It gives us a clean API and solves multiple problems. It has been started to land on major browsers and JS engines as Chrome 73+ / Node 12+...
User recognition without cookies or local storage
...ople are so security-aware that it would be difficult to get people to install these kinds of programs on their system. This leaves you stuck with using Cookies and other, similar tools.
Cookies and other, similar tools
You might consider building a Data Profile, then using Probability tests to id...
background function in Python
...em is. I've got a function that downloads the image needed and saves it locally. Right now it's run inline with the code that displays a message to the user, but that can sometimes take over 10 seconds for non-local images. Is there a way I could call this function when it's needed, but run it in t...
LEFT JOIN only first row
... Thanks for your fast response. This was not the exact answer, but totally got me on the right way. I always tried to join both on the same level instead of making the one depended from the other. Thank you very much for leading me on the right track. Edited the first post
...
Practical usage of setjmp and longjmp in C
...n me where exactly setjmp() and longjmp() functions can be used practically in embedded programming? I know that these are for error handling. But I'd like to know some use cases.
...