1 - vector R language self-study

R - 向量

RThe basic information unit of language is called vector（vector）.There are different types of vector,包括数值向量（numeric）、整数向量（integer）、The text vector（character）、Boolean value vector（logical）、日期向量（Date）与Date/time vector（POSIXct）.

1. 创建向量

用 <- Will be assigned to different types of data objects can create length as1的向量.使用函数class() Can know what type of objects is vector.

Create the length is more than1的向量

利用c()函数,The pen more information comma-separated placed into a thing of.

Generates repeat data vector

利用rep()函数,其中timesParameters can be specified in the vector to several duplicate values.

2. 数值向量

可以使用seq()函数或 : Which is based on symbols regularity value vector.

from指定起始值,toSpecify termination,bySpecify the numerical spacing.

Generate numerical spacing for1的数值向量.

No matter the input Numbers with or without decimal digits,RLanguage preset stored in numeric vector.

3. 整数向量

Enter an integer, and add capital English lettersLAs a note,RLanguage will be stored as an integer vector.

If the decimal digits with unnecessary zero,RLanguage will still be stored as an integer vector.

If the decimal digits with necessary zero,RLanguage will be stored as numeric vector.

数学运算

+、-、、/：加减乘除
^ 或 **：次方
%/%：Returns the quotient
%%：Back the remainder

4. The text vector

使用单引号 ’ ’ 或 双引号 " " Establish a text vector.

When in single quotes and single quotes,Or double quotation marks and the double quotes,You can use a jump backslash characters \ .

Embedded in the text vector has been declared a good vector

利用 sprintf() 函数,以 %s The text vector,以 %f As a numeric vector.

5. Boolean value vector

Boolean value vector is TRUE 与 FALSE 两个值,也可以简写成T和F.

R语言是 case-sensitive 的,True或者true不等于TRUE.

逻辑运算符号

• ==、!= ：Is and is not equal to
• >、 >=、 <、 <= ：大于、大于等于、小于、小于等于
• %in%：包含于
• !：非

TRUE跟数值1相等;FALSE跟数值0相等.