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How to add an auto-incrementing primary key to an existing table, in PostgreSQL?
...h this solution is that if the table already contains rows then you get an error: SQL Error [23502]: ERROR: column "id" contains null values
– isapir
Mar 7 '18 at 16:30
3
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How to force the browser to reload cached CSS/JS files?
I have noticed that some browsers (in particular, Firefox and Opera) are very zealous in using cached copies of .css and .js files, even between browser sessions. This leads to a problem when you update one of these files but the user's browser keeps on using the cached copy.
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Can anyone explain IEnumerable and IEnumerator to me? [closed]
Can anyone explain IEnumerable and IEnumerator to me?
16 Answers
16
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Returning multiple values from a C++ function
... put the function definition of divide into a separate cpp file? I get the error error: use of ‘auto divide(int, int)’ before deduction of ‘auto’. How do I solve this?
– Adriaan
Feb 23 '18 at 20:26
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Sample random rows in dataframe
...ow make it better by checking first if n<=nrow(df) and stopping with an error.
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How to print colored text in Python?
...e end string at the end.
CRED = '\033[91m'
CEND = '\033[0m'
print(CRED + "Error, does not compute!" + CEND)
This produces the following in bash, in urxvt with a Zenburn-style color scheme:
Through experimentation, we can get more colors:
Note: \33[5m and \33[6m are blinking.
This way we ca...
How do I write the 'cd' command in a makefile?
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@Beta: well yes, and a dash prefix ignores the error status as well. Maybe I got a little carried away, I wanted to point out the fact that make does echos the command, regardless of what kind of command it is. And in this case, it's a command with no output, which makes ...
Changing MongoDB data store directory
...your solution but when I am restarting the application it giving following error - 2019-11-18T18:58:45.215+1100 I STORAGE [initandlisten] exception in initAndListen: 28596 Unable to determine status of lock file in the data directory /var/lib/mongo: boost::filesystem::status: Permission denied: "/v...
Android get free size of internal/external memory
...rmatSize(availableBlocks * blockSize);
} else {
return ERROR;
}
}
public static String getTotalExternalMemorySize() {
if (externalMemoryAvailable()) {
File path = Environment.getExternalStorageDirectory();
StatFs stat = new StatFs(...
Check if a variable is of function type
...rence (open your javascript console and reload page, there might be logged error messages). Note: Revision 3 added isFunctionD (based on only typeof == "function") - and it seems to be much faster than Underscore's "fast" version.
– Joel Purra
Feb 2 '12 at 18:3...