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Determine the data types of a data frame's columns
...se ?str(). To explore some examples, let's make some data:
set.seed(3221) # this makes the example exactly reproducible
my.data <- data.frame(y=rnorm(5),
x1=c(1:5),
x2=c(TRUE, TRUE, FALSE, FALSE, FALSE),
X3=letters[1:5])
@...
浅析为什么char类型的范围是 -128~+127 - C/C++ - 清泛网 - 专注C/C++及内核技术
浅析为什么char类型的范围是 -128~+127在C语言中， signed char 类型的范围为-128~127,每本教科书上也这么写，但是没有哪一本书上（包括老师）也不会给你为什么是-128~127，这...在C语言中， signed char 类型的范围为-128~127,每本教科书上...
What is the bower (and npm) version syntax?
...example: to indicate you'll take any subsequent patch-level changes on the 1.2.x tree, starting with 1.2.0, but less than 1.3.0, you could use:
"angular": "~1.2"
or:
"angular": "~1.2.0"
This also gets you the same results as using the .x syntax:
"angular": "1.2.x"
But, you can use the tilde...
Replace all 0 values to NA
...
Replacing all zeroes to NA:
df[df == 0] <- NA
Explanation
1. It is not NULL what you should want to replace zeroes with. As it says in ?'NULL',
NULL represents the null object in R
which is unique and, I guess, can be seen as the most uninformative and empty object.1 Then it b...
Custom numeric format string to always display the sign
...
301
Yes, you can.
There is conditional formatting. See Conditional formatting in MSDN
eg:
string...
Why does ++[[]][+[]]+[+[]] return the string “10”?
This is valid and returns the string "10" in JavaScript ( more examples here ):
9 Answers
...
Pandas index column title or name
...'
In [8]: df.index.name = 'foo'
In [9]: df.index.name
Out[9]: 'foo'
In [10]: df
Out[10]:
Column 1
foo
Apples 1
Oranges 2
Puppies 3
Ducks 4
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Is MATLAB OOP slow or am I doing something wrong?
...t; call_nops
Computer: PCWIN Release: 2009b
Calling each function/method 100000 times
nop() function: 0.02261 sec 0.23 usec per call
nop1-5() functions: 0.02182 sec 0.22 usec per call
nop() subfunction: 0.02244 sec 0.22 usec per call
@()[] anonymous f...
What is the difference between Ruby 1.8 and Ruby 1.9
I'm not clear on the differences between the "current" version of Ruby (1.8) and the "new" version (1.9). Is there an "easy" or a "simple" explanation of the differences and why it is so different?
...