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Print all but the first three columns
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50
A solution that does not add extra leading or trailing whitespace:
awk '{ for(i=4; i<NF; i++...
What are best practices for validating email addresses on iOS 2.0
... the cleanest way to validate an email address that a user enters on iOS 2.0?
13 Answers
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Rails detect if request was AJAX
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edited Jul 10 '15 at 16:46
answered Nov 22 '11 at 1:08
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Print an integer in binary format in Java
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Assuming you mean "built-in":
int x = 100;
System.out.println(Integer.toBinaryString(x));
See Integer documentation.
(Long has a similar method, BigInteger has an instance method where you can specify the radix.)
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R - Concatenate two dataframes?
... line adds column b to data frame b.
Results
> a <- data.frame(a=c(0,1,2), b=c(3,4,5), c=c(6,7,8))
> a
a b c
1 0 3 6
2 1 4 7
3 2 5 8
> b <- data.frame(a=c(9,10,11), c=c(12,13,14))
> b
a c
1 9 12
2 10 13
3 11 14
> b$b <- NA
> b
a c b
1 9 12 NA
2 10 13 NA
3 11...
What's the difference between echo, print, and print_r in PHP?
...s you have in your variables. Consider this test program:
$values = array(0, 0.0, false, '');
var_dump($values);
print_r ($values);
With print_r you can't tell the difference between 0 and 0.0, or false and '':
array(4) {
[0]=>
int(0)
[1]=>
float(0)
[2]=>
bool(false)
[3]=...
What's quicker and better to determine if an array key exists in PHP?
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10 Answers
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VC MFC工具栏(CToolBar)控件 - C/C++ - 清泛网 - 专注C/C++及内核技术
...钮控件显示的区域（大小）相对于父窗口
ButtonRect.left=10;
ButtonRect.top=10;
ButtonRect.right=80;
ButtonRect.bottom=30;
m_Button.Create("动态创建",WS_CHILD,ButtonRect,this,1115);
m_Button.ShowWindow(SW_SHOW);//显示按钮控件
知道了怎样动态创建按钮控件，...
How to add an empty column to a dataframe?
...t; df = pd.DataFrame({"A": [1,2,3], "B": [2,3,4]})
>>> df
A B
0 1 2
1 2 3
2 3 4
>>> df["C"] = ""
>>> df["D"] = np.nan
>>> df
A B C D
0 1 2 NaN
1 2 3 NaN
2 3 4 NaN
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How to create circle with Bézier curves?
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10 Answers
10
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