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Warning message: In `…` : invalid factor level, NA generated
... of 2 variables:
$ Type : Factor w/ 1 level "": NA 1 1
$ Amount: chr "100" "0" "0"
>
> fixed <- data.frame("Type" = character(3), "Amount" = numeric(3),stringsAsFactors=FALSE)
> fixed[1, ] <- c("lunch", 100)
> str(fixed)
'data.frame': 3 obs. of 2 variables:
$ Type : chr ...
Create an empty object in JavaScript with {} or new Object()?
... Array(); over []; - with one minor exception:
var emptyArray = new Array(100);
creates a 100 item long array with all slots containing undefined - which may be nice/useful in certain situations (such as (new Array(9)).join('Na-Na ') + 'Batman!').
My recommendation
Never use new Object(); - i...
Java switch statement multiple cases
...l the time:
switch (variable)
{
case 5:
case 6:
etc.
case 100:
doSomething();
break;
}
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How do I create a nice-looking DMG for Mac OS X using command-line tools?
...ner window to false
set the bounds of container window to {400, 100, 885, 430}
set theViewOptions to the icon view options of container window
set arrangement of theViewOptions to not arranged
set icon size of theViewOptions to 72
set background...
Join a list of strings in python and wrap each string in quotation marks
...t;> timeit.Timer("""words = ['hello', 'world', 'you', 'look', 'nice'] * 100; ', '.join('"{0}"'.format(w) for w in words)""").timeit(1000)
0.32559704780578613
>>> timeit.Timer("""words = ['hello', 'world', 'you', 'look', 'nice'] * 100; '"{}"'.format('", "'.join(words))""").timeit(1000)
0...
Maintaining the final state at end of a CSS3 animation
...fter animation ends. for example if your animation changes width from 0 to 100px, this property makes sure the element remains 100px wide after animation ends.
– Farzad YZ
Feb 17 '16 at 15:23
...
How to clear the interpreter console?
...
Well, here's a quick hack:
>>> clear = "\n" * 100
>>> print clear
>>> ...do some other stuff...
>>> print clear
Or to save some typing, put this file in your python search path:
# wiper.py
class Wipe(object):
def __repr__(self):
...
how to find host name from IP with out login to the host
...
For Windows, try:
NBTSTAT -A 10.100.3.104
or
ping -a 10.100.3.104
For Linux, try:
nmblookup -A 10.100.3.104
They are almost same.
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How does the Java 'for each' loop work?
... the testing class at the bottom of this post, which sums the numbers in a 100-element primitive-int array (A is iterator, B is index):
[C:\java_code\]java TimeIteratorVsIndexIntArray 1000000
Test A: 358,597,622 nanoseconds
Test B: 269,167,681 nanoseconds
B faster by 89,429,941 nanoseconds (24.4387...
When NOT to use Cassandra?
... cause real problems with banks. Scenario:You have one bank account, with $100 on above the limit on it, and two bank cards. When you try to withdraw money with the two cards at the same time at 2 different ATMs, you will get 2 times $100, and a letter with an extra fee in your mail box. The bank ea...