大约有 3,516 项符合查询结果（耗时：0.0183秒） [XML]
Is there a regular expression to detect a valid regular expression?
...any invalid POSIX EREs. Notably, they are a bit pickier in character class ranges, e.g. this is valid in PCRE but not in ERE: [a-b-c].
– Pedro Gimeno
Dec 25 '19 at 19:39
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How do I append one string to another in Python?
...end result is that the operation is amortized O(n).
e.g.
s = ""
for i in range(n):
s+=str(i)
used to be O(n^2), but now it is O(n).
From the source (bytesobject.c):
void
PyBytes_ConcatAndDel(register PyObject **pv, register PyObject *w)
{
PyBytes_Concat(pv, w);
Py_XDECREF(w);
}
/...
What are the differences between PMD and FindBugs?
...Boolean values, impossible cast, 32bit int shifted by an amount not in the range of 0-31, a collection which contains itself, equals method always returns true, an infinite loop, etc.
Usually each of them finds a different set of problems. Use both. These tools taught me a lot about how to write go...
How to set a Django model field's default value to a function call / callable (e.g., a date relative
...(string.ascii_uppercase + string.digits + string.ascii_lowercase) for _ in range(random.randint(3, 5)))
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Convert Unicode to ASCII without errors in Python
...eError: 'ascii' codec can't decode byte 0xa0 in position 0: ordinal not in range(128)
While:
html = '\xa0'
decoded_str = html.decode("windows-1252")
encoded_str = decoded_str.encode("utf8")
Succeeds without error. Do note that "windows-1252" is something I used as an example. I got this from ch...
C# How can I check if a URL exists/is valid?
...
I would add that some status codes in the 3xx range will actually cause an error to be thrown e.g. 304 Not Modified in which case you should be handling that in your catch block
– RobV
Aug 25 '11 at 8:43
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When to use NSInteger vs. int
...better suited to even a long. Maybe you know that it wont exceed a certain range, and therefore think it will be more memory-efficient to simply use int.
– Jacob Relkin
Dec 14 '10 at 23:27
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Performance of Java matrix math libraries? [closed]
...between Java libraries and while there is no clear winner across the whole range of operations, there are a few clear leaders as can be seen in the latest performance results (October 2013).
If you are working with "large" matrices and can use native libraries, then the clear winner (about 3.5x fas...
How to set a single, main title above all the subplots with Pyplot?
...ort matplotlib.pyplot as plt
import numpy as np
fig=plt.figure()
data=np.arange(900).reshape((30,30))
for i in range(1,5):
ax=fig.add_subplot(2,2,i)
ax.imshow(data)
fig.suptitle('Main title') # or plt.suptitle('Main title')
plt.show()
...
Moving and vanishing lines of code; trouble with Eclipse's XML Editor
...oth save and format your XML.
I've tried other editors options like "Show range indicator" or "Use characters to show changes in vertical ruler" but I didn't see any difference in behavior with activating or de-activating these options.
Finally, to correct the visual display of the file when it's ...