大约有 35,419 项符合查询结果（耗时：0.0493秒） [XML]
Python, Matplotlib, subplot: How to set the axis range?
How can I set the y axis range of the second subplot to e.g. [0,1000] ?
The FFT plot of my data (a column in a text file) results in a (inf.?) spike so that the actual data is not visible.
...
Relative frequencies / proportions with dplyr
...n = n()) %>%
mutate(freq = n / sum(n))
# am gear n freq
# 1 0 3 15 0.7894737
# 2 0 4 4 0.2105263
# 3 1 4 8 0.6153846
# 4 1 5 5 0.3846154
From the dplyr vignette:
When you group by multiple variables, each summary peels off one level of the grouping. That makes ...
Is there any boolean type in Oracle databases?
...read on asktom. From recommending CHAR(1) 'Y'/'N' they switch to NUMBER(1) 0/1 when someone points out that 'Y'/'N' depends on the English language, while e.g. German programmers might use 'J'/'N' instead.
The worst thing is that they defend this stupid decision just like they defend the ''=NULL st...
How to wait in bash for several subprocesses to finish and return exit code !=0 when any subprocess
...ral subprocesses spawned from that script to finish and return exit code !=0 when any of the subprocesses ends with code !=0 ?
...
How to reuse an ostringstream?
...lear, then seek the appropriate sequence to the begin:
s.clear();
s.seekp(0); // for outputs: seek put ptr to start
s.seekg(0); // for inputs: seek get ptr to start
That will prevent some reallocations done by str by overwriting whatever is in the output buffer currently instead. Results are like...
Check if an array is empty or exists
...
if (typeof image_array !== 'undefined' && image_array.length > 0) {
// the array is defined and has at least one element
}
Your problem may be happening due to a mix of implicit global variables and variable hoisting. Make sure you use var whenever declaring a variable:
<?php e...
Accessing localhost:port from Android emulator
...
420
You can access your host machine with the IP address "10.0.2.2".
This has been designed in thi...
Regex to validate password strength
...itive look ahead assertions:
^(?=.*[A-Z].*[A-Z])(?=.*[!@#$&*])(?=.*[0-9].*[0-9])(?=.*[a-z].*[a-z].*[a-z]).{8}$
Rubular link
Explanation:
^ Start anchor
(?=.*[A-Z].*[A-Z]) Ensure string has two uppercase letters.
(?=.*[!@#$&*]) Ensure string ha...
Convert string with commas to array
... JSON.parse("[" + string + "]");
This gives you an Array of numbers.
[0, 1]
If you use .split(), you'll end up with an Array of strings.
["0", "1"]
Just be aware that JSON.parse will limit you to the supported data types. If you need values like undefined or functions, you'd need to use ...
Java: int array initializes with nonzero elements
... bug will be fixed.
There is only advice at the moment: do not use JDK1.7.0_04 or later if you depend on JLS for newly declared arrays.
Update at October 5:
In the new Build 10 of the JDK 7u10 (early access) released at October 04, 2012, this bug was fixed at least for Linux OS (I did not test fo...