Programming Erlang exercise 3.10

1. 快速浏览3.1.3节，然后测试并记忆这些行编辑命令

命令	说明	助记法
^A	行首	A为第一个字母
^D	删除当前字符	D为Delete
^E	行尾	E为End
^F	向前的字符	F为Forward
^B	向后的字符	B为Back
^P	前一行	P为Preceding
^N	下一行	N为Next
^T	调换最近两个字符的位置	T为Transposition
Tab	尝试扩展当前模块或函数的名称

^在Mac中按键为：Control

2. 在shell里面输入help()命令。你将看到一长串命令。可以试一试其中一些命令。

yfydemacbook-pro:opensource yfy$ erl
Erlang/OTP 18 [erts-7.2.1] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]

Eshell V7.2.1  (abort with ^G)
1> help().
** shell internal commands **
b()        -- display all variable bindings
e(N)       -- repeat the expression in query <N>
f()        -- forget all variable bindings
f(X)       -- forget the binding of variable X
h()        -- history
history(N) -- set how many previous commands to keep
results(N) -- set how many previous command results to keep
catch_exception(B) -- how exceptions are handled
v(N)       -- use the value of query <N>
rd(R,D)    -- define a record
rf()       -- remove all record information
rf(R)      -- remove record information about R
rl()       -- display all record information
rl(R)      -- display record information about R
rp(Term)   -- display Term using the shell's record information
rr(File)   -- read record information from File (wildcards allowed)
rr(F,R)    -- read selected record information from file(s)
rr(F,R,O)  -- read selected record information with options
** commands in module c **
bt(Pid)    -- stack backtrace for a process
c(File)    -- compile and load code in <File>
cd(Dir)    -- change working directory
flush()    -- flush any messages sent to the shell
help()     -- help info
i()        -- information about the system
ni()       -- information about the networked system
i(X,Y,Z)   -- information about pid <X,Y,Z>
l(Module)  -- load or reload module
lc([File]) -- compile a list of Erlang modules
ls()       -- list files in the current directory
ls(Dir)    -- list files in directory <Dir>
m()        -- which modules are loaded
m(Mod)     -- information about module <Mod>
memory()   -- memory allocation information
memory(T)  -- memory allocation information of type <T>
nc(File)   -- compile and load code in <File> on all nodes
nl(Module) -- load module on all nodes
pid(X,Y,Z) -- convert X,Y,Z to a Pid
pwd()      -- print working directory
q()        -- quit - shorthand for init:stop()
regs()     -- information about registered processes
nregs()    -- information about all registered processes
uptime()   -- print node uptime
xm(M)      -- cross reference check a module
y(File)    -- generate a Yecc parser
** commands in module i (interpreter interface) **
ih()       -- print help for the i module
true
2>	

3. 试着用一个元组来表示一座房子，再用一个房子列表来表示一条街道。请确保你能向这些结构中加入数据或从中取出数据。

Erlang的所有数据类型：Data Types

类型	说明
Terms	A piece of data of any data type
Number	two types of numeric literals, integers and floats
Atom	An atom is a literal, a constant with name 如果是以大写字母开前头则需要用’’号括起来
Bit Strings and Binaries	A bit string is used to store an area of untyped memory.
Reference	A reference is a term that is unique in an Erlang runtime system
Fun	A fun is a functional object.
Port Identifier	A port identifier identifies an Erlang port.
Pid	A process identifier, pid, identifies a process.
Tuple	A tuple is a compound data type with a fixed number of terms.
Map	A map is a compound data type with a variable number of key-value associations.
List	A list is a compound data type with a variable number of terms.
String	Strings are enclosed in double quotes (“), but is not a data type in Erlang.
Record	A record is a data structure for storing a fixed number of elements.
Boolean	There is no Boolean data type in Erlang. Instead the atoms true and false are used to denote Boolean values.
Escape Sequences	具体查看上面数据类型链接

房子：

House1={house,{owner,yangfy1},{location,’china cq1’}}

House2={house,{owner,yangfy2},{location,’china cq2’}}

House3={house,{owner,yangfy3},{location,’china cq3’}}

街道：

ShaZhengjie=[House1,House2,House3]

Eshell V7.2.1  (abort with ^G)
1> House1={house,{owner,yangfy1},{location,'china cq1'}}.
{house,{owner,yangfy1},{location,'china cq1'}}
2> House2={house,{owner,yangfy2},{location,'china cq2'}}.
{house,{owner,yangfy2},{location,'china cq2'}}
3> House3={house,{owner,yangfy3},{location,'china cq3'}}.
{house,{owner,yangfy3},{location,'china cq3'}}
4> ShaZhengjie=[House1,House2,House3].
[{house,{owner,yangfy1},{location,'china cq1'}},
 {house,{owner,yangfy2},{location,'china cq2'}},
 {house,{owner,yangfy3},{location,'china cq3'}}]
5>

读取House1中location;House2的owner

5> {house,_,{_,D}} = House1.
{house,{owner,yangfy1},{location,'china cq1'}}
6> D.
'china cq1'
7> {house,{_,O},_} = House2.
{house,{owner,yangfy2},{location,'china cq2'}}
8> O.
yangfy2

读取街道中第二栋房子的owner

9> [H1,H2|H3] = ShaZhengjie.
[{house,{owner,yangfy1},{location,'china cq1'}},
 {house,{owner,yangfy2},{location,'china cq2'}},
 {house,{owner,yangfy3},{location,'china cq3'}}]
10> {house,{_,O1},_}=H2.
{house,{owner,yangfy2},{location,'china cq2'}}
11> O1.
yangfy2

为街道新增加一栋房子

House4={house,{owner,yangfy4},{location,’china cq4’}}

12> House4={house,{owner,yangfy4},{location,'china cq4'}}.
{house,{owner,yangfy4},{location,'china cq4'}}
13> ShaZhengjie1 = [House4|ShaZhengjie].
[{house,{owner,yangfy4},{location,'china cq4'}},
 {house,{owner,yangfy1},{location,'china cq1'}},
 {house,{owner,yangfy2},{location,'china cq2'}},
 {house,{owner,yangfy3},{location,'china cq3'}}]
16>