Erlang 数 2015.05.12

gistfile1.erl

## http://erlangworld.web.fc2.com/data_types/number.html
## Leaning Erlang 2015.05.12 

yoshida-book% erl
Erlang/OTP 17 [erts-6.4] [source] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false]

Eshell V6.4  (abort with ^G)
1> 42.
42
2> 3.7.
3.7
3> 4/7.
0.5714285714285714
4>  9/4.
2.25
5> 8 div 5.
1
6> 7 rem 3.
1
7> X = 123456789.
123456789
8> X * X * X * X * X.
28679718602997181072337614380936720482949
9> 16#A.
10
10> 8#13.
11
11> is_number(-3.4).
true
12> is_number({hello,3}).
false
13> is_integer(8).
true
14> is_integer(3.3).
false
15> is_float(8).
false
16> is_float(1.3).
true
17> abs(-3.33).
3.33
18> abs(-3).
3
19> round(5.5).
6
20> round(5.4).
5
21> trunc(5.5).
5
22> float(55).
55.0
23> integer_to_list(77).
"77"
24> list_to_integer("123").
123
25> list_to_integer('123').
** exception error: bad argument
     in function  list_to_integer/1
        called as list_to_integer('123')
26> erlang:integer_to_list(1023, 16).
"3FF"
27> float_to_List(7.0).
** exception error: undefined shell command float_to_List/1
28> float_to_list(7.0).
"7.00000000000000000000e+00"
29> list_to_float("2.2017764e+0").
2.2017764
30>