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理解Python的 with 语句 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
... convenient way of dealing with the situation where you have to do a setup and teardown to make something happen. A very good example for this is the situation where you want to gain a handler to a file, read data from the file and the close the file handler.
有一些任务，可能事先需要设...
In Django, how do I check if a user is in a certain group?
...
then user.groups.all() returns [<Group: Editor>].
Alternatively, and more directly, you can check if a a user is in a group by:
if django_user.groups.filter(name = groupname).exists():
...
Note that groupname can also be the actual Django Group object.
...
Variable interpolation in the shell
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What is the difference between using ${} and double quotes? Should I prefer one over the other?
– user31389
Mar 10 '18 at 10:49
3
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How to add include path in Qt Creator?
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If you are using qmake, the standard Qt build system, just add a line to the .pro file as documented in the qmake Variable Reference:
INCLUDEPATH += <your path>
If you are using your own build system, you create a project by selecting "Import of ...
Get UIScrollView to scroll to the top
...animated:YES];
or if you want to preserve the horizontal scroll position and just reset the vertical position:
[self.scrollView setContentOffset:CGPointMake(self.scrollView.contentOffset.x, 0)
animated:YES];
share
...
Return positions of a regex match() in Javascript?
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if (match) {
console.log("match found at " + match.index);
}
And for multiple matches:
var re = /bar/g,
str = "foobarfoobar";
while ((match = re.exec(str)) != null) {
console.log("match found at " + match.index);
}
...
Count character occurrences in a string in C++
...rns type iterator_traits<InputIt>::difference_type, which for most standard containers is std::ptrdiff_t, not std::size_t.
– Daniel Stevens
Apr 15 at 7:48
add a comment
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How do you automatically set text box to Uppercase?
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It is also not a good idea to have the spaces between the attribute name and the value...
<input type="text" class="normal"
name="Name" size="20" maxlength="20"
style="text-transform:uppercase" />
<img src="../images/tickmark.gif" border="0" />
Please note this tran...
Rails 3 check if attribute changed
...ns an array of the attributes changed for that object.
Both @user.changed and attrs are arrays so I can get the intersection (see ary & other ary method). The result of the intersection is an array. By calling any? on the array, I get true if there is at least one intersection.
Also very usefu...
Split delimited strings in a column and insert as new rows [duplicate]
...parate_rows function as described by @Tif below.
It works so much better, and it allows to "unnest" multiple columns in a single statement:
> head(mydf)
geneid chrom start end strand length gene_count
ENSG00000223972.5 chr1;chr1;chr1;chr1;chr1;chr1;chr1;chr1;chr1 11869;1...