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Best way to select random rows PostgreSQL
... @Awesome-o: The goal is to retrieve 1000 rows, I start with an extra 10 % to compensate for a few gaps or (unlikely but possible) duplicate random numbers ... the explanation is in my answer.
– Erwin Brandstetter
Feb 24 '14 at 12:53
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How to make unicode string with python3
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Literal strings are unicode by default in Python3.
Assuming that text is a bytes object, just use text.decode('utf-8')
unicode of Python2 is equivalent to str in Python3, so you can also write:
str(text, 'utf-8')
if you prefer.
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How to append rows to an R data frame
...<- function(n){
df <- data.frame(x = numeric(n), y = character(n), stringsAsFactors = FALSE)
for(i in 1:n){
df$x[i] <- i
df$y[i] <- toString(i)
}
df
}
Here's a similar approach, but one where the data.frame is created as the last step.
# Use preallocated vectors
f4 <...
How do I disable fail_on_empty_beans in Jackson?
...izationFeature.FAIL_ON_EMPTY_BEANS, false);
// do various things, perhaps:
String someJsonString = mapper.writeValueAsString(someClassInstance);
SomeClass someClassInstance = mapper.readValue(someJsonString, SomeClass.class)
The StackOverflow link below also has an example for a Spring project.
F...
How to concatenate strings of a string field in a PostgreSQL 'group by' query?
I am looking for a way to concatenate the strings of a field within a group by query. So for example, I have a table:
14 An...
Java: Integer equals vs. ==
...s small integers.
If the value p being boxed is true, false, a byte, a char in the range \u0000 to \u007f, or an int or short number between -128 and 127, then let r1 and r2 be the results of any two boxing conversions of p. It is always the case that r1 == r2.
Resources :
JLS - Boxing
O...
How can I auto-elevate my batch file, so that it requests from UAC administrator rights if required?
...Note that you need to use for to be able to take advantage of the advanced string functions, such as %%~nk, which extracts just the filename.
Optimized script structure, improvements (added variable vbsGetPrivileges which is now referenced everywhere allowing to change the path or name of the file e...
Looking for jQuery find(..) method that includes the current node
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@ronen An extra file for something which can be done in one line? Thanks, but no thanks.
– user659025
Nov 18 '15 at 14:58
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How to remove item from array by value? [duplicate]
...n my application and its purpose. It saves me thinking time so that I have extra time to make the application better and not worrying about the small functions that makeup my application. Someone already invented the wheel, why would someone remake it every time they build a car?
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Testing whether a value is odd or even
... the following? I only tested this in IE, but it was quite happy to handle strings representing numbers of any length, actual numbers that were integers or floats, and both functions returned false when passed a boolean, undefined, null, an array or an object. (Up to you whether you want to ignore l...