大约有 15,461 项符合查询结果（耗时：0.0181秒） [XML]
Finding ALL duplicate rows, including “elements with smaller subscripts”
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Hold on, I just ran a test and found I was wrong: x <- c(1:9, 7:10, 5:22); y <- c(letters, letters[1:5]); test <- data.frame(x, y); test[duplicated(test$x) | duplicated(test$x, fromLast=TRUE), ] Returned all three of he copies of 7, 8, an...
how to check the dtype of a column in python pandas
...ol'). It may be used even for selecting groups of columns based on dtype:
test = pd.DataFrame({'bool' :[False, True], 'int64':[-1,2], 'int32':[-1,2],'float': [-2.5, 3.4],
'compl':np.array([1-1j, 5]),
'dt' :[pd.Timestamp('2013-01-02'), pd.Timestamp('2016-1...
Query for documents where array size is greater than 1
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I believe this is the fastest query that answers your question, because it doesn't use an interpreted $where clause:
{$nor: [
{name: {$exists: false}},
{name: {$size: 0}},
{name: {$size: 1}}
]}
It means "all documents except those with...
Why should I use Hamcrest-Matcher and assertThat() instead of traditional assertXXX()-Methods
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It also helps with the "rule" of one assertion per test and blends more easily with BDD-style specifications.
– Nils Wloka
Nov 20 '09 at 14:10
2
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SQLite: How do I save the result of a query as a CSV file?
...v-mode and switch to file output.
sqlite> .mode csv
sqlite> .output test.csv
sqlite> select * from tbl1;
sqlite> .output stdout
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How to rsync only a specific list of files?
...s to ignore the .. giving me an error like rsync: link_stat "/home/michael/test/subdir/test.txt" failed: No such file or directory (in this case running from the "test" dir and trying to specify "../subdir/test.txt" which does exist.
– Michael
Nov 2 '16 at 0:09...
Using XPATH to search text containing
...d.
We use the same normalization logic on
the text of HTML Selenese test case
tables. This has a number of
advantages. First, you don't need to
look at the HTML source of the page to
figure out what your assertions should
be; "&nbsp;" symbols are invisible
to the end user, and...
How to find whether or not a variable is empty in Bash
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In Bash at least the following command tests if $var is empty:
if [[ -z "$var" ]]; then
# Do what you want
fi
The command man test is your friend.
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Referring to the null object in Python
... Python; instead there's None. As stated already, the most accurate way to test that something has been given None as a value is to use the is identity operator, which tests that two variables refer to the same object.
>>> foo is None
True
>>> foo = 'bar'
>>> foo is None
F...
Proper usage of Java -D command-line parameters
... the problem is that you've put the "-D" after the -jar. Try this:
java -Dtest="true" -jar myApplication.jar
From the command line help:
java [-options] -jar jarfile [args...]
In other words, the way you've got it at the moment will treat -Dtest="true" as one of the arguments to pass to main i...