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ActiveRecord: size vs count
... don't know what you are doing, use size...
count
Resolves to sending a Select count(*)... query to the DB. The way to go if you don't need the data, but just the count.
Example: count of new messages, total elements when only a page is going to be displayed, etc.
length
Loads the required dat...
Is there a NumPy function to return the first index of something in an array?
...st element. Note also that where and nonzero return arrays, so you need to select the first element to get the index.
In [71]: np.argmax(a==2)
Out[71]: 2
In [72]: np.where(a==2)
Out[72]: (array([2], dtype=int64),)
In [73]: np.nonzero(a==2)
Out[73]: (array([2], dtype=int64),)
Time comparison
Ju...
How do I add a ToolTip to a control?
...
Add a ToolTip component to your form
Select one of the controls that you want a tool tip for
Open the property grid (F4), in the list you will find a property called "ToolTip on toolTip1" (or something similar). Set the desired tooltip text on that property.
Rep...
How to empty a Heroku database
...
If you already have multiple gems installed, you may be presented with:
Select gem to uninstall:
1. heroku-2.25.0
2. heroku-2.26.2
3. All versions
Just uninstall #2 and rerun the command. Joy!
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可重入函数、不可重入函数及线程安全 - C/C++ - 清泛网 - 专注C/C++及内核技术
...elset
tcsetattr
cfsetospeed
geteuid
pselect
sigemptyset
tcsetpgrp
chdir
getgid
raise
sigfillset
time
chmod
getgroups
read
sigismember
timer_getoverrun
...
What is the difference between statically typed and dynamically typed languages?
...t core to the language and usable on demand.
When it comes to technology selection, neither side has an intrinsic superiority over the other. It is just a matter of preference whether you want more control to begin with or flexibility. just pick the right tool for the job, and make sure to check w...
What is aria-label and how should I use it?
...t can I do in my browser (chrome) to hear this? And how can a blind person select this button if he have no idea where it is?
– Salvador Dali
Feb 26 '14 at 11:57
1
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How to add a custom button state
...tion indicated by @(Ted Hopp) works, but needs a little correction: in the selector, the item states need an "app:" prefix, otherwise the inflater won't recognise the namespace correctly, and will fail silently; at least this is what happens to me.
Allow me to report here the whole solution, with s...
Learning Python from Ruby; Differences and Similarities
...lues greater than 15. In Ruby, you'd have to write the following:
values.select {|v| v > 15}.map {|v| v * v}
The Ruby code doesn't feel as compact. It's also not as efficient since it first converts the values array into a shorter intermediate array containing the values greater than 15. Th...
Best way to check if a Data Table has a null value in it
... || dr1["Columnname"].ToString() == ""
select Columnname);
Here Replace Columnname with table column name and "" your search item in above code we looking null value.
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