大约有 23,000 项符合查询结果（耗时：0.0355秒） [XML]
Difference between HashMap, LinkedHashMap and TreeMap
...
private TreeMap<String ,Integer> mySection2 = new TreeMap<>(); mySection2.put("abc1", 2); mySection2.put("abc2",5); mySection2.put("abc3",3); ...
How to drop rows of Pandas DataFrame whose value in a certain column is NaN
...ilippSchwarz This error occurs if the column (EPS in the example) contains strings or other types that cannot be digested by np.isfinite(). I recommend to use pandas.notnull() that will handle this more generously.
– normanius
Apr 5 '18 at 10:02
...
What is a good reason to use SQL views?
... T_NEW) but one that has data for both active and inactive users, with one extra column active.
If your system(s) have gazillion queries that do SELECT whatever FROM T_OLD WHERE whatever, you have two choices for the roll-out:
1) Cold Turkey - Change the DB, and at the same time, change, test and ...
How to enable/disable bluetooth programmatically in android
...
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals(BluetoothAdapter.ACTION_STATE_CHANGED)) {
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,
...
Bash script to receive and repass quoted parameters
...# $4= "ddd ddd"
"$*" - quoted-dollar-star smashes the args into a single string (~1% of the time you actually want this behavior, eg in a conditional: if [[ -z "$*" ]]; then ...):
./quoted-dollar-star.sh aaa '' "'cc cc'" '"ddd ddd"'
# $1= aaa 'cc cc' "ddd ddd"
# $2=
...
Return 0 if field is null in MySQL
...) returns expr1; otherwise it returns expr2. IFNULL() returns a numeric or string value, depending on the context in which it is used.
share
|
improve this answer
|
follow
...
How does IPython's magic %paste work?
...est_mode which allows you to copy paste example and test snippets from doc strings. This is also useful to execute interactive python session output that you could find in documentation and online forums, without having to first strip out the prompt strings.
...
bash assign default value
...riable without needing to reassign
# colons suppress attempting to run the string
unset EGGS
: ${EGGS=spam}
echo 1 $EGGS # 1 spam
unset EGGS
: ${EGGS:=spam}
echo 2 $EGGS # 2 spam
EGGS=
: ${EGGS=spam}
echo 3 $EGGS # 3 (set, but blank -> leaves alone)
EGGS=
: ${EGGS:=spam}
echo ...
Printing 1 to 1000 without loop or conditionals
...es, blowing up the code size, right? You might as well generate the output string itself instead of a thousand printfs.
– Darius Bacon
Jan 3 '11 at 8:44
...
What is JavaScript garbage collection?
...called a "scavenger". A scavenger
may refer to a number, an object, a
string, whatever. We maintain a list
of scavengers -- variables are moved
on to the scav list when they come
into scope and off the scav list when
they go out of scope.
Every now and then the garbage
collector ru...