This is an R Markdown document. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. For more details on using R Markdown see http://rmarkdown.rstudio.com.

When you click the Knit button a document will be generated that includes both content as well as the output of any embedded R code chunks within the document. You can embed an R code chunk like this:

summary(cars)

##      speed           dist       
##  Min.   : 4.0   Min.   :  2.00  
##  1st Qu.:12.0   1st Qu.: 26.00  
##  Median :15.0   Median : 36.00  
##  Mean   :15.4   Mean   : 42.98  
##  3rd Qu.:19.0   3rd Qu.: 56.00  
##  Max.   :25.0   Max.   :120.00

##      speed           dist       
##  Min.   : 4.0   Min.   :  2.00  
##  1st Qu.:12.0   1st Qu.: 26.00  
##  Median :15.0   Median : 36.00  
##  Mean   :15.4   Mean   : 42.98  
##  3rd Qu.:19.0   3rd Qu.: 56.00  
##  Max.   :25.0   Max.   :120.00

summary(cars)

summary(cars)

You can also embed plots, for example:

Note that the echo = FALSE parameter was added to the code chunk to prevent printing of the R code that generated the plot.

Markdown Quick Reference

R markdown is an easy-to-write plain text format for creating dynamic documents and report.See Using R Markdown to learn more.

{r,echo=TRUE,eval=FALSE,fig.height=2/8,fig.width=2/8,message=FALSE,warning=FALSE,include=FALSE,results='markup'/'asis'/'hold'/'hide',fig.align='left'/'right'/'center',}

Emphasis

*italic* _italic_  
**blod** __blod__

Demonstrate:
italic italic
blod blod

Headers

# Header 1
## Header 2
### Header 3
#### Header 4
##### Header 5
###### Header 6

Demonstrate:

Header 1

Header 2

Header 3

Header 4

Header 5

Header 6

Lists

underlist

* Item 1
* Item 2
    + Item 2a
    + Item 2b

Demonstrate:

Item 1
Item 2
- Item 2a
- Item 2b

Ordered List:

1. Item 1
2. Item 2
3. Item 3
    + Item 3a
    + Item 3b

Demonstrate:

Item 1
Item 2
Item 3
- Item 3a
- Item 3b

Manual Line Breaks

End a line with two or more spaces:

Roses are red,  
Violets are blue.

Demonstrate:

Roses are red,
Violets are blue.

Links

Use a plain http address or add a link to a phrase:

[Using R Markdown](http://rmarkdown.rstudio.com/)

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Using R Markdown

Images

Images on the web or local files in the same directory:

![alt text](http://example.com/logo.png)

![alt text](figures/img.png)

Local image: alt text

Internet Image: alt text

Blockquotes

A friend once said:

> It's always better to give 
> than to receive.

Demonstrate:

A friend once said:

It’s always better to give than to receive.

R Code Blocks

R code will be evaluated and printed

summary(cars$dist)

##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##    2.00   26.00   36.00   42.98   56.00  120.00

summary(cars$speed)

##    Min. 1st Qu.  Median    Mean 3rd Qu.    Max. 
##     4.0    12.0    15.0    15.4    19.0    25.0

Inline R Code

There were `r nrow(cars)` cars studied

Demonstrate:

There were 50 cars studied

Plain Code Blocks

Plain code blocks are displayed in a fixed-width font but not evaulated

This text is displayed verbatim / preformatted

Demonstrate:

This text is displayed verbatim / preformatted

Inline Code

We defined the `add` function to 
compute the sum of two numbers.

Demonstrate:

We defined the add function to compute the sum of two numbers.

LaTeX Equations

Inline Equation

$a + b$

Demonstrate:

\(a + b\)

Display Equation

$$ a +b = c $$
<math ...> </math>          #What's the meaning ?

Demonstrate:

\[ a +b = c \]

Horizontal Rule / Page Break

Three or more asterisks or dashes:

******
------

Demonstrate:

Tables

First Header  | Second Header
------------- | -------------
Content Cell  | Content Cell
Content Cell  | Content Cell

Demonstrate:

First Header	Second Header
Content Cell	Content Cell
Content Cell	Content Cell

knitr::kable(mtcars)

	mpg	cyl	disp	hp	drat	wt	qsec	vs	am	gear	carb
Mazda RX4	21.0	6	160.0	110	3.90	2.620	16.46	0	1	4	4
Mazda RX4 Wag	21.0	6	160.0	110	3.90	2.875	17.02	0	1	4	4
Datsun 710	22.8	4	108.0	93	3.85	2.320	18.61	1	1	4	1
Hornet 4 Drive	21.4	6	258.0	110	3.08	3.215	19.44	1	0	3	1
Hornet Sportabout	18.7	8	360.0	175	3.15	3.440	17.02	0	0	3	2
Valiant	18.1	6	225.0	105	2.76	3.460	20.22	1	0	3	1
Duster 360	14.3	8	360.0	245	3.21	3.570	15.84	0	0	3	4
Merc 240D	24.4	4	146.7	62	3.69	3.190	20.00	1	0	4	2
Merc 230	22.8	4	140.8	95	3.92	3.150	22.90	1	0	4	2
Merc 280	19.2	6	167.6	123	3.92	3.440	18.30	1	0	4	4
Merc 280C	17.8	6	167.6	123	3.92	3.440	18.90	1	0	4	4
Merc 450SE	16.4	8	275.8	180	3.07	4.070	17.40	0	0	3	3
Merc 450SL	17.3	8	275.8	180	3.07	3.730	17.60	0	0	3	3
Merc 450SLC	15.2	8	275.8	180	3.07	3.780	18.00	0	0	3	3
Cadillac Fleetwood	10.4	8	472.0	205	2.93	5.250	17.98	0	0	3	4
Lincoln Continental	10.4	8	460.0	215	3.00	5.424	17.82	0	0	3	4
Chrysler Imperial	14.7	8	440.0	230	3.23	5.345	17.42	0	0	3	4
Fiat 128	32.4	4	78.7	66	4.08	2.200	19.47	1	1	4	1
Honda Civic	30.4	4	75.7	52	4.93	1.615	18.52	1	1	4	2
Toyota Corolla	33.9	4	71.1	65	4.22	1.835	19.90	1	1	4	1
Toyota Corona	21.5	4	120.1	97	3.70	2.465	20.01	1	0	3	1
Dodge Challenger	15.5	8	318.0	150	2.76	3.520	16.87	0	0	3	2
AMC Javelin	15.2	8	304.0	150	3.15	3.435	17.30	0	0	3	2
Camaro Z28	13.3	8	350.0	245	3.73	3.840	15.41	0	0	3	4
Pontiac Firebird	19.2	8	400.0	175	3.08	3.845	17.05	0	0	3	2
Fiat X1-9	27.3	4	79.0	66	4.08	1.935	18.90	1	1	4	1
Porsche 914-2	26.0	4	120.3	91	4.43	2.140	16.70	0	1	5	2
Lotus Europa	30.4	4	95.1	113	3.77	1.513	16.90	1	1	5	2
Ford Pantera L	15.8	8	351.0	264	4.22	3.170	14.50	0	1	5	4
Ferrari Dino	19.7	6	145.0	175	3.62	2.770	15.50	0	1	5	6
Maserati Bora	15.0	8	301.0	335	3.54	3.570	14.60	0	1	5	8
Volvo 142E	21.4	4	121.0	109	4.11	2.780	18.60	1	1	4	2

Reference Style Links and Images

Links

A [linked phrase][id]. 

At the bottom of the document:

[id]: http://example.com/ "Title"

Images

![alt text][id]

At the bottom of the document:

[id]: figures/img.png "Title"

Miscellaneous

superscript^2^
~~strikethrough~~

Demonstrate:

superscript²
~~strikethrough~~

Caching

Typographic Entities

ASCII characters are transformed into typographic HTML entities:
Straight quotes ( " and ' ) into “curly” quotes
Dashes (“--” and “---”) into en- and em-dash entities
Three consecutive dots (“...”) into an ellipsis entity

R_Markdown study

王哲峰

Thu Aug 18 00:12:04 2016

Markdown Quick Reference

Emphasis

Headers

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Header 6

Lists

underlist

Ordered List:

Manual Line Breaks

End a line with two or more spaces:

Links

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Images

Images on the web or local files in the same directory:

Blockquotes

R Code Blocks

R code will be evaluated and printed

Inline R Code

Plain Code Blocks

Plain code blocks are displayed in a fixed-width font but not evaulated

Inline Code

LaTeX Equations

Inline Equation

Display Equation

Horizontal Rule / Page Break

Three or more asterisks or dashes:

Tables

Reference Style Links and Images

Links

Images

Miscellaneous

Caching

Typographic Entities