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Convert column classes in data.table
...oblem using data.table: How do I convert column classes? Here is a simple em>x m>ample: With data.frame I don't have a problem converting it, with data.table I just don't know how:
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Getting Syntam>x m>Error for print with keyword argument end=' '
...ave this python script where I need to run gdal_retile.py ,
but I get an em>x m>ception on this line:
14 Answers
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How to take the first N items from a generator or list in Python? [duplicate]
...Slicing a list
top5 = array[:5]
To slice a list, there's a simple syntam>x m>: array[start:stop:step]
You can omit any parameter. These are all valid: array[start:], array[:stop], array[::step]
Slicing a generator
import itertools
top5 = itertools.islice(my_list, 5) # grab the first five element...
Bitwise operation and usage
...wise it's 0.
OR is 1 if one or both of its inputs are 1, otherwise it's 0.
m>X m>OR is 1 only if em>x m>actly one of its inputs are 1, otherwise it's 0.
NOT is 1 only if its input is 0, otherwise it's 0.
These can often be best shown as truth tables. Input possibilities are on the top and left, the resulta...
Does it make sense to use “as” instead of a cast even if there is no null check? [closed]
In development blogs, online code em>x m>amples and (recently) even a book, I keep stumbling about code like this:
13 Answers
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Convert nullable bool? to bool
...will represent. If null should be false, you can do this:
bool newBool = m>x m>.HasValue ? m>x m>.Value : false;
Or:
bool newBool = m>x m>.HasValue && m>x m>.Value;
Or:
bool newBool = m>x m> ?? false;
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How to install a specific JDK on Mac OS m>X m>?
I want to install a specific JDK (the latest for em>x m>ample). For this, I went to the JDK download homepage: http://java.sun.com/javase/downloads/indem>x m>.jsp .
I looked for a Mac version, but I'm a bit surprised to only see downloadable versions for Linum>x m>, Windows and Solaris ...
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Structure padding and packing
... char gap_1[3]; /* -"-: for alignment of the whole struct in an array */
} m>x m>;
Packing, on the other hand prevents compiler from doing padding - this has to be em>x m>plicitly requested - under GCC it's __attribute__((__packed__)), so the following:
struct __attribute__((__packed__)) mystruct_A {
c...
equals vs Arrays.equals in Java
..., i.e. is it the same array. As @alf points out it's not what most people em>x m>pect.
Arrays.equals(array1, array2) compares the contents of the arrays.
Similarly array.toString() may not be very useful and you need to use Arrays.toString(array).
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How do I use itertools.groupby()?
I haven't been able to find an understandable em>x m>planation of how to actually use Python's itertools.groupby() function. What I'm trying to do is this:
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