1.语法老在变，第一个是0.3版文档中的例子，{}表示向量语法已经废弃，第2个是0.6版文档的例子，在0.5版中是无效的，只有0.51自带文档中的例子可以执行。

```julia> for T = {Int8,Int16,Int32,Int64,Int128,Uint8,Uint16,Uint32,Uint64,Uint128}
end
ERROR: syntax: { } vector syntax is discontinued

julia> for T = [Int8,Int16,Int32,Int64,Int128,Uint8,Uint16,Uint32,Uint64,Uint128]
end
ERROR: UndefVarError: Uint8 not defined
in anonymous at .\:?

julia> for T in [Int8,Int16,Int32,Int64,Int128,UInt8,UInt16,UInt32,UInt64,UInt128]
end
Int8: [-128,127]
Int16: [-32768,32767]
Int32: [-2147483648,2147483647]
Int64: [-9223372036854775808,9223372036854775807]
Int128: [-170141183460469231731687303715884105728,170141183460469231731687303715884105727]
UInt8: [0,255]
UInt16: [0,65535]
UInt32: [0,4294967295]
UInt64: [0,18446744073709551615]
UInt128: [0,340282366920938463463374607431768211455]

julia>  x =Int128(2)^Int128(3)^Int128(4)
2417851639229258349412352
```

2.测试程序用时

```julia> @elapsed [x for x in 1:10^6];

julia> @elapsed [x for x in 1:10^6]
0.151227431

julia> @elapsed [x for x in 1:10^7]
0.179493186

julia> @timed [x for x in 1:10^7]
([1,2,3,4,5,6,7,8,9,10  …  9999991,9999992,9999993,9999994,9999995,9999996,9999
997,9999998,9999999,10000000],0.147096148,40360520,0.098642467,Base.GC_Diff(4036
0520,1,0,12060,0,0,98642467,1,1))

julia> @time [x for x in 1:10^7]
0.175094 seconds (12.06 k allocations: 38.491 MB, 57.12% gc time)
10000000-element Array{Int32,1}:
1
2
3
4
5
6
7
8
9
10
⋮
9999991
9999992
9999993
9999994
9999995
9999996
9999997
9999998
9999999
10000000

julia> tic(); [x for x in 1:10^7];toc()
elapsed time: 0.193216436 seconds
0.193216436

julia> tic(); [x for x in 1:10^7];toq()
0.070731702
```

3.二进制位的显示

```julia>  x =Int128(2)^Int128(3)^Int128(4)
2417851639229258349412352

julia> bits(x)
"00000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000000
000000000"

julia> bits(3.14)
"0100000000001001000111101011100001010001111010111000010100011111"

julia> bits(Float64(3.14))
"0100000000001001000111101011100001010001111010111000010100011111"

julia> bits(Float32(3.14))
"01000000010010001111010111000011"

julia> bits(Float16(3.14))
"0100001001001000"

```