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Check if a Bash array contains a value
In Bash, what is the simplest way to test if an array contains a certain value?
35 Answers
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jQuery: Check if div with certain class name exists
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You can simplify this by checking the first object that is returned from JQuery like so:
if ($(".mydivclass")[0]){
// Do something if class exists
} else {
// Do something if class does not exist
}
In this case if there is a tr...
What is the idiomatic Go equivalent of C's ternary operator?
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As pointed out (and hopefully unsurprisingly), using if+else is indeed the idiomatic way to do conditionals in Go.
In addition to the full blown var+if+else block of code, though, this spelling is also used often:
index := val
if val <= 0 {
index = -val
}
and if you ...
What is the best way to test for an empty string with jquery-out-of-the-box?
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if (!a) {
// is emtpy
}
To ignore white space for strings:
if (!a.trim()) {
// is empty or whitespace
}
If you need legacy support (IE8-) for trim(), use $.trim or a polyfill.
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Python `if x is not None` or `if not x is None`?
I've always thought of the if not x is None version to be more clear, but Google's style guide and PEP-8 both use if x is not None . Is there any minor performance difference (I'm assuming not), and is there any case where one really doesn't fit (making the other a clear winner for my convent...
水果vs蔬菜智能分类器 - EdgeML图像识别项目 · App Inventor 2 中文网
...目实现步骤
第一步：了解 Personal Image Classifier (PIC)
PIC扩展的主要功能：
与传统机器学习的区别：
第二步：使用 PIC 训练自定义模型
1. 数...
PostgreSQL create table if not exists
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This feature has been implemented in Postgres 9.1:
CREATE TABLE IF NOT EXISTS myschema.mytable (i integer);
For older versions, here is a function to work around it:
CREATE OR REPLACE FUNCTION create_mytable()
RETURNS void
LANGUAGE plpgsql AS
$func$
BEGIN
IF EXISTS (SELECT FROM ...
It is more efficient to use if-return-return or if-else-return?
Suppose I have an if statement with a return . From the efficiency perspective, should I use
8 Answers
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SQL: IF clause within WHERE clause
Is it possible to use an IF clause within a WHERE clause in MS SQL?
14 Answers
14
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How can I determine the direction of a jQuery scroll event?
...= 0;
$(window).scroll(function(event){
var st = $(this).scrollTop();
if (st > lastScrollTop){
// downscroll code
} else {
// upscroll code
}
lastScrollTop = st;
});
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