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Add column with constant value to pandas dataframe [duplicate]
...numpy.random import randint
In [9]: df = DataFrame({'a': randint(3, size=10)})
In [10]:
In [10]: df
Out[10]:
a
0 0
1 2
2 0
3 1
4 0
5 0
6 0
7 0
8 0
9 0
In [11]: s = df.a[:5]
In [12]: dfa, sa = df.align(s, axis=0)
In [13]: dfa
Out[13]:
a
0 0
1 2
2 0
3 1
4 0
5 0
6 0
7 0
8 ...
How to get first and last day of previous month (with timestamp) in SQL Server
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select DATEADD(MONTH, DATEDIFF(MONTH, 0, GETDATE())-1, 0) --First day of previous month
select DATEADD(MONTH, DATEDIFF(MONTH, -1, GETDATE())-1, -1) --Last Day of previous month
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What does the ^ operator do in Java?
...perator.
Let's take 5^6 as example:
(decimal) (binary)
5 = 101
6 = 110
------------------ xor
3 = 011
This the truth table for bitwise (JLS 15.22.1) and logical (JLS 15.22.2) xor:
^ | 0 1 ^ | F T
--+----- --+-----
0 | 0 1 F | F T
1 | 1 0 T | T...
Automatically expanding an R factor into a collection of 1/0 indicator variables for every factor le
...vel, there is an associated column in a new data frame, which contains a 1/0 indicator. E.g., suppose I have:
8 Answers
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Gray out image with CSS?
...age" src="something.jpg" />
</div>
css:
#myImage {
opacity: 0.4;
filter: alpha(opacity=40); /* msie */
}
/* or */
#wrapper {
opacity: 0.4;
filter: alpha(opacity=40); /* msie */
background-color: #000;
}
...
Two color borders
...utline is inside of the shadow; in FireFox it is outside, so -moz-outline: 0 is useful to ensure that you don't get a gnarly line around your beautiful CSS drop shadow).
.someclass {
border: 1px solid blue;
outline: 1px solid darkblue;
}
Edit: Some people have remarked that outline doesn't ji...
SQL Logic Operator Precedence: And and Or
...e's an example to illustrate:
Declare @x tinyInt = 1
Declare @y tinyInt = 0
Declare @z tinyInt = 0
Select Case When @x=1 OR @y=1 And @z=1 Then 'T' Else 'F' End -- outputs T
Select Case When (@x=1 OR @y=1) And @z=1 Then 'T' Else 'F' End -- outputs F
For those who like to consult references (in al...
Regular expression for matching latitude/longitude coordinates?
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answered Aug 19 '10 at 3:38
Eric CEric C
3,55633 gold badges2828 silver badges2626 bronze badges
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How to validate an Email in PHP?
...LTER_VALIDATE_EMAIL)
PHP Manual filter_var()
Available in PHP >= 5.2.0
If you don't want to change your code that relied on your function, just do:
function isValidEmail($email){
return filter_var($email, FILTER_VALIDATE_EMAIL) !== false;
}
Note: For other uses (where you need Regex)...
Modifying a subset of rows in a pandas dataframe
...fy this DataFrame (or create a copy) so that B is always NaN whenever A is 0. How would I achieve that?
5 Answers
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