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Troubleshooting “Illegal mix of collations” error in mysql
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This is generally caused by comparing two strings of incompatible collation or by attempting to select data of different collation into a combined column.
The clause COLLATE allows you to specify the collation used in the query.
For exa...
How to get the currently logged in user's user id in Django?
...rs = [{user.id: user.get_name()} for user in logged_in_users]
# Query all logged in staff users based on id list
all_staff_users = CustomUser.objects.filter(is_resident=False, is_active=True, is_superuser=False)
logged_out_users = list()
# for some reason exclude() would not work co...
What is the fastest integer division supporting division by zero no matter what the result is?
...x, int y)
{
y += y == 0;
return x/y;
}
The compiler basically recognizes that it can use a condition flag of the test in the addition.
As per request the assembly:
.globl f
.type f, @function
f:
pushl %ebp
xorl %eax, %eax
movl %esp, %ebp
movl 12(%...
mongo group query how to keep fields
...are accumulated/funneled/reduced) doesn't make so much sense even theoretically. However, sorting before hand is actually inefficient compared to sorting each group within themselves since sorting algorithms are more complex than O(n). I wish there would be better ways in MongoDB.
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Variable interpolation in the shell
I have a variable called filepath=/tmp/name .
3 Answers
3
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How can I get a precise time, for example in milliseconds in Objective-C?
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Actually this is precise enough for the general use case.
– logancautrell
Jul 2 '12 at 12:30
4
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Mailto links do nothing in Chrome but work in Firefox?
...omputer. I know at work, it will run thunderbird; if they have outlook installed it may run outlook, etc. Personally, it did not run gmail by default, I had to set it up that way.
– kennypu
Jul 14 '13 at 1:55
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Preferred method to store PHP arrays (json_encode vs serialize)
...ciative array of data in a flat file for caching purposes. I might occasionally come across the need to convert it to JSON for use in my web app but the vast majority of the time I will be using the array directly in PHP.
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How to set environment variables in Python?
I need to set some environment variables in the Python script and I want all the other scripts that are called from Python to see the environment variables' set.
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How to reshape data from long to wide format
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The reshape comments and similar argument names aren't all that helpful. However, I have found that for long to wide, you need to provide data = your data.frame, idvar = the variable that identifies your groups, v.names = the variables that will become multiple columns in wide f...