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Performant Entity Serialization: BSON vs MessagePack (vs JSON)
...:2} is stored in a file and you want to update the value of "a" from 1 to 2000.
With MessagePack, 1 uses only 1 byte but 2000 uses 3 bytes. So "b" must be moved backward by 2 bytes, while "b" is not modified.
With BSON, both 1 and 2000 use 5 bytes. Because of this verbosity, you don't have to move...
Int division: Why is the result of 1/3 == 0?
...se returns the true result of division rounded towards zero. The result of 0.333... is thus rounded down to 0 here. (Note that the processor doesn't actually do any rounding, but you can think of it that way still.)
Also, note that if both operands (numbers) are given as floats; 3.0 and 1.0, or eve...
Pretty printing XML with javascript
...;xsl:output indent="yes"/> instruction:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:template match="node()|@*">
<xsl:copy>
<xsl:apply-templates select="...
Change one value based on another value in pandas
... for you.
import pandas
df = pandas.read_csv("test.csv")
df.loc[df.ID == 103, 'FirstName'] = "Matt"
df.loc[df.ID == 103, 'LastName'] = "Jones"
As mentioned in the comments, you can also do the assignment to both columns in one shot:
df.loc[df.ID == 103, ['FirstName', 'LastName']] = 'Matt', 'Jone...
pandas read_csv and filter columns with usecols
...andas as pd
from StringIO import StringIO
csv = r"""dummy,date,loc,x
bar,20090101,a,1
bar,20090102,a,3
bar,20090103,a,5
bar,20090101,b,1
bar,20090102,b,3
bar,20090103,b,5"""
df = pd.read_csv(StringIO(csv),
header=0,
index_col=["date", "loc"],
usecols=["date", "loc", "x"],
...
Select by partial string from a pandas DataFrame
...
Based on github issue #620, it looks like you'll soon be able to do the following:
df[df['A'].str.contains("hello")]
Update: vectorized string methods (i.e., Series.str) are available in pandas 0.8.1 and up.
...
Efficient way to insert a number into a sorted array of numbers?
...
Just as a single data point, for kicks I tested this out inserting 1000 random elements into an array of 100,000 pre-sorted numbers using the two methods using Chrome on Windows 7:
First Method:
~54 milliseconds
Second Method:
~57 seconds
So, at least on this setup, the native method doesn...
How can I ensure that a division of integers is always rounded up?
...
670
UPDATE: This question was the subject of my blog in January 2013. Thanks for the great question!...
How to reshape data from long to wide format
...
answered May 4 '11 at 23:20
ChaseChase
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How to position a div in the middle of the screen when the page is bigger than the screen
...it at http://jsfiddle.net/XEUbc/1/
#mydiv {
position:fixed;
top: 50%;
left: 50%;
width:30em;
height:18em;
margin-top: -9em; /*set to a negative number 1/2 of your height*/
margin-left: -15em; /*set to a negative number 1/2 of your width*/
border: 1px solid #ccc;
...