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Most efficient way to increment a Map value in Java
...ood answers to this question--thanks folks--so I decided to run some tests and figure out which method is actually fastest. The five methods I tested are these:
the "ContainsKey" method that I presented in the question
the "TestForNull" method suggested by Aleksandar Dimitrov
the "AtomicLong" meth...
Officially, what is typename for?
... week, I was declaring two iterators as members of another templated class and I had to do this)...
8 Answers
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MySQL Insert into multiple tables? (Database normalization?)
...
No, you can't insert into multiple tables in one MySQL command. You can however use transactions.
BEGIN;
INSERT INTO users (username, password)
VALUES('test', 'test');
INSERT INTO profiles (userid, bio, homepage)
VALUES(LAST_INSERT_ID(),'Hello world!', 'http://www.stackoverflow...
How can I programmatically get the MAC address of an iphone
How to programmatically get an iPhone's MAC address and IP address?
12 Answers
12
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MySQL: Can't create table (errno: 150)
I am trying to import a .sql file and its failing on creating tables.
34 Answers
34
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Pass a data.frame column name to a function
...want to save the user from typing all those quotes, one option might be to convert bare, unquoted column names to strings using deparse(substitute()):
new_column2 <- function(df,col_name,col1,col2){
col_name <- deparse(substitute(col_name))
col1 <- deparse(substitute(col1))
col...
How do I create delegates in Objective-C?
I know how delegates work, and I know how I can use them.
19 Answers
19
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Differences between Perl and PHP [closed]
...rators. In Perl, if you use <, >, ==, !=, <=>, and so on, Perl converts both operands to numbers. If you want to convert as strings instead, you have to use lt, gt, eq, ne, cmp (the respective equivalents of the operators listed previously). Examples where this will really get you:
if (...
In Scala, what exactly does 'val a: A = _' (underscore) mean?
...default value of the type A. For example, the default value of an Int is 0 and the default value of a reference type is null.
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In Postgresql, force unique on combination of two columns
...l1, col2)
)
autoincrement is not postgresql. You want a serial.
If col1 and col2 make a unique and can't be null then they make a good primary key:
CREATE TABLE someTable (
col1 int NOT NULL,
col2 int NOT NULL,
primary key (col1, col2)
)
...