. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4 变量 17 4.1 合法的变量名 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.2 sqrt(100) 10.0 julia> sqrt = 4 ERROR: cannot assign a value to variable Base.sqrt from module Main 4.1 合法的变量名 变量名字必须以英文字母（A-Z 或 a-z）、下划线或编码大于 00A0 的 Unicode 字符的一个子集开头。具 体来说指的是，Unicode 字符分类中的 Lu/Ll/Lt/ con- verted, an error is raised. Examples julia> promote(Int8(1), Float16(4.5), Float32(4.1)) (1.0f0, 4.5f0, 4.1f0) source Base.oftype – Function. oftype(x, y) Convert y to the type of x (convert(typeof(x)

. . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 Integers and Floating-Point Numbers 13 4.1 Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLOATING-POINT NUMBERS Type Precision Number of bits Float16 half 16 Float32 single 32 Float64 double 64 4.1 Integers Literal integers are represented in the standard manner: julia> 1 1 julia> 1234 1234 julia> Int Int32 julia> UInt UInt32 # 64-bit system: julia> Int Int64 julia> UInt UInt64 4.1. INTEGERS 15 Larger integer literals that cannot be represented using only 32 bits but can be represented

. . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 Integers and Floating-Point Numbers 13 4.1 Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLOATING-POINT NUMBERS Type Precision Number of bits Float16 half 16 Float32 single 32 Float64 double 64 4.1 Integers Literal integers are represented in the standard manner: julia> 1 1 julia> 1234 1234 julia> Int Int32 julia> UInt UInt32 # 64-bit system: julia> Int Int64 julia> UInt UInt64 4.1. INTEGERS 15 Larger integer literals that cannot be represented using only 32 bits but can be represented

. . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 Integers and Floating-Point Numbers 11 4.1 Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLOATING-POINT NUMBERS Type Precision Number of bits Float16 half 16 Float32 single 32 Float64 double 64 4.1 Integers Literal integers are represented in the standard manner: julia> 1 1 julia> 1234 1234 julia> Int Int32 julia> UInt UInt32 # 64-bit system: julia> Int Int64 julia> UInt UInt64 4.1. INTEGERS 13 Larger integer literals that cannot be represented using only 32 bits but can be represented

. . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 Integers and Floating-Point Numbers 11 4.1 Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLOATING-POINT NUMBERS Type Precision Number of bits Float16 half 16 Float32 single 32 Float64 double 64 4.1 Integers Literal integers are represented in the standard manner: julia> 1 1 julia> 1234 1234 julia> Int Int32 julia> UInt UInt32 # 64-bit system: julia> Int Int64 julia> UInt UInt64 4.1. INTEGERS 13 Larger integer literals that cannot be represented using only 32 bits but can be represented

. . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 Integers and Floating-Point Numbers 13 4.1 Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLOATING-POINT NUMBERS Type Precision Number of bits Float16 half 16 Float32 single 32 Float64 double 64 4.1 Integers Literal integers are represented in the standard manner: julia> 1 1 julia> 1234 1234 julia> Int Int32 julia> UInt UInt32 # 64-bit system: julia> Int Int64 julia> UInt UInt64 4.1. INTEGERS 15 Larger integer literals that cannot be represented using only 32 bits but can be represented

. . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 Integers and Floating-Point Numbers 11 4.1 Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLOATING-POINT NUMBERS Type Precision Number of bits Float16 half 16 Float32 single 32 Float64 double 64 4.1 Integers Literal integers are represented in the standard manner: julia> 1 1 julia> 1234 1234 julia> Int Int32 julia> UInt UInt32 # 64-bit system: julia> Int Int64 julia> UInt UInt64 4.1. INTEGERS 13 Larger integer literals that cannot be represented using only 32 bits but can be represented

. . . . . . . . . . . . . . . . . . . . . . . . . . 9 4 Integers and Floating-Point Numbers 11 4.1 Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLOATING-POINT NUMBERS Type Precision Number of bits Float16 half 16 Float32 single 32 Float64 double 64 4.1 Integers Literal integers are represented in the standard manner: julia> 1 1 julia> 1234 1234 julia> Int Int32 julia> UInt UInt32 # 64-bit system: julia> Int Int64 julia> UInt UInt64 4.1. INTEGERS 13 Larger integer literals that cannot be represented using only 32 bits but can be represented

. . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 Integers and Floating-Point Numbers 13 4.1 Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLOATING-POINT NUMBERS Type Precision Number of bits Float16 half 16 Float32 single 32 Float64 double 64 4.1 Integers Literal integers are represented in the standard manner: julia> 1 1 julia> 1234 1234 julia> Int Int32 julia> UInt UInt32 # 64-bit system: julia> Int Int64 julia> UInt UInt64 4.1. INTEGERS 15 Larger integer literals that cannot be represented using only 32 bits but can be represented

. . . . . . . . . . . . . . . . . . . . . . . . . . 11 4 Integers and Floating-Point Numbers 13 4.1 Integers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FLOATING-POINT NUMBERS Type Precision Number of bits Float16 half 16 Float32 single 32 Float64 double 64 4.1 Integers Literal integers are represented in the standard manner: julia> 1 1 julia> 1234 1234 julia> Int Int32 julia> UInt UInt32 # 64-bit system: julia> Int Int64 julia> UInt UInt64 4.1. INTEGERS 15 Larger integer literals that cannot be represented using only 32 bits but can be represented