大约有 48,000 项符合查询结果（耗时：0.0363秒） [XML]
Best way to make Java's modulus behave like it should with negative numbers?
...
Maarten Bodewes
76.4k1212 gold badges114114 silver badges213213 bronze badges
answered Dec 10 '10 at 18:46
Peter LawreyPete...
Take the content of a list and append it to another list
...
You probably want
list2.extend(list1)
instead of
list2.append(list1)
Here's the difference:
>>> a = range(5)
>>> b = range(3)
>>> c = range(2)
>>> b.append(a)
>>> b
[0, 1, 2, [0, 1, 2, 3, 4]]
>...
mongodb group values by multiple fields
...
207
TLDR Summary
In modern MongoDB releases you can brute force this with $slice just off the bas...
deleting rows in numpy array
...numpy.delete method.
Suppose I have the following array x:
x = array([[1,2,3],
[4,5,6],
[7,8,9]])
To delete the first row, do this:
x = numpy.delete(x, (0), axis=0)
To delete the third column, do this:
x = numpy.delete(x,(2), axis=1)
So you could find the indices of the row...
Appending an element to the end of a list in Scala
...
List(1,2,3) :+ 4
Results in List[Int] = List(1, 2, 3, 4)
Note that this operation has a complexity of O(n). If you need this operation frequently, or for long lists, consider using another data type (e.g. a ListBuffer).
...
How to loop through all but the last item of a list?
...
324
for x in y[:-1]
If y is a generator, then the above will not work.
...
Getting the count of unique values in a column in bash
... see a frequency count for column two (for example):
awk -F '\t' '{print $2}' * | sort | uniq -c | sort -nr
fileA.txt
z z a
a b c
w d e
fileB.txt
t r e
z d a
a g c
fileC.txt
z r a
v d c
a m c
Result:
3 d
2 r
1 z
1 m
1 g
1...
How to merge 2 JSON objects from 2 files using jq?
...t will merge them recursively. For example,
jq -s '.[0] * .[1]' file1 file2
Important: Note the -s (--slurp) flag, which puts files in the same array.
Would get you:
{
"value1": 200,
"timestamp": 1382461861,
"value": {
"aaa": {
"value1": "v1",
"value2": "v2",
"value3...
Assign pandas dataframe column dtypes
...ated in 0.17)
df = pd.DataFrame({'x': {0: 'a', 1: 'b'}, 'y': {0: '1', 1: '2'}, 'z': {0: '2018-05-01', 1: '2018-05-02'}})
df.dtypes
x object
y object
z object
dtype: object
df
x y z
0 a 1 2018-05-01
1 b 2 2018-05-02
You can apply these to each column you want to co...
Uninstall old versions of Ruby gems
...
|
edited Dec 28 '13 at 23:39
Steven Penny
76.1k4545 gold badges296296 silver badges336336 bronze badges
...