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Adding one day to a date
My code to add one day to a date returns a date before day adding:
2009-09-30 20:24:00 date after adding one day SHOULD be rolled over to the next month: 1970-01-01 17:33:29
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How do multiple clients connect simultaneously to one port, say 80, on a server? [duplicate]
...tination port" header field.
Now, there are two answers to your question, one for stateful protocols and one for stateless protocols.
For a stateless protocol (ie UDP), there is no problem because "connections" don't exist - multiple people can send packets to the same port, and their packets will...
Putting an if-elif-else statement on one line?
...itional operator? (the question is about condensing if-else statement to one line)
11 Answers
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Concatenate multiple result rows of one column into one, group by another column [duplicate]
I'm having a table like this
2 Answers
2
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Add new column with foreign key constraint in one command
...rations separated by commas. For example...
Informix syntax:
ALTER TABLE one
ADD two_id INTEGER,
ADD CONSTRAINT FOREIGN KEY(two_id) REFERENCES two(id);
The syntax for IBM DB2 LUW is similar, repeating the keyword ADD but (if I read the diagram correctly) not requiring a comma to separate...
How does the HyperLogLog algorithm work?
...ve been learning about different algorithms in my spare time recently, and one that I came across which appears to be very interesting is called the HyperLogLog algorithm - which estimates how many unique items are in a list.
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Why does one use dependency injection?
...posable, IEnumerable or IPrintable. A class is an actual implementation of one or more of these interfaces: List or Map may both be implementations of IEnumerable.
To get the point: Often your classes depend on each other. E.g. you could have a Database class which accesses your database (hah, surp...
The Use of Multiple JFrames: Good or Bad Practice? [closed]
... The user sees multiple icons in their task bar when expecting to see only one. Plus the side effects of the coding problems..
A nightmare to code and maintain:
A modal dialog offers the easy opportunity to focus attention on the content of that dialog - choose/fix/cancel this, then proceed. Mul...
How does one remove an image in Docker?
... Remove untagged images: docker rmi $(docker images | grep "^<none>" | awk "{print $3}")
– Barrett Clark
Oct 5 '15 at 16:11
1
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Call apply-like function on each row of dataframe with multiple arguments from each row
...from the dplyr package:
> library(dplyr)
> myf <- function(tens, ones) { 10 * tens + ones }
> x <- data.frame(hundreds = 7:9, tens = 1:3, ones = 4:6)
> mutate(x, value = myf(tens, ones))
hundreds tens ones value
1 7 1 4 14
2 8 2 5 25
3 9 ...