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How to get first element in a list of tuples?
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>>> a = [(1, u'abc'), (2, u'def')]
>>> [i[0] for i in a]
[1, 2]
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Bash, no-arguments warning, and case decisions
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if [[ $# -eq 0 ]] ; then
echo 'some message'
exit 0
fi
case "$1" in
1) echo 'you gave 1' ;;
*) echo 'you gave something else' ;;
esac
The Advanced Bash-Scripting Guide is pretty good. In spite of its name, it does treat...
Turn a number into star rating display using jQuery and CSS
...tars, span.stars span {
display: block;
background: url(stars.png) 0 -16px repeat-x;
width: 80px;
height: 16px;
}
span.stars span {
background-position: 0 0;
}
Image
(source: ulmanen.fi)
Note: do NOT hotlink to the above image! Copy the file to your own server and u...
Awk学习笔记 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...达式元字符
8. POSIX字符集
9. 匹配操作符(~)
10. 比较表达式
11. 范围模板
12. 一个验证passwd文件有效性的例子
13. 几个实例
14. awk编程
14.1. 变量
14.2. BEGIN模块
14.3. END模块
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Checking if a string can be converted to float in Python
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Richard Simões
10.6k44 gold badges3737 silver badges4949 bronze badges
answered Apr 9 '09 at 21:55
dbrdbr
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Creating a new column based on if-elif-else condition
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140
To formalize some of the approaches laid out above:
Create a function that operates on the rows...
What does value & 0xff do in Java?
... = value;
then result would end up with the value ff ff ff fe instead of 00 00 00 fe. A further subtlety is that the & is defined to operate only on int values1, so what happens is:
value is promoted to an int (ff ff ff fe).
0xff is an int literal (00 00 00 ff).
The & is applied to yield...
What does ~~ (“double tilde”) do in Javascript?
...result is a number.
In other words, it yields:
function(x) {
if(x < 0) return Math.ceil(x);
else return Math.floor(x);
}
only if x is between -(231) and 231 - 1. Otherwise, overflow will occur and the number will "wrap around".
This may be considered useful to convert a function's string...
Removing leading zeroes from a field in a SQL statement
...ve the leading zeroes from a particular field, which is a simple VARCHAR(10) field. So, for example, if the field contains '00001A', the SELECT statement needs to return the data as '1A'.
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Clear icon inside input text
...ch" to your input
The support is pretty decent but will not work in IE<10
<input type="search">
Clearable input for old browsers
If you need IE9 support here are some workarounds
Using a standard <input type="text"> and some HTML elements:
/**
* Clearable text ...