IDL变量和数组使用

1、变量定义

①将变量转换为合法变量

IDL> print,idl_validname('a bac',/convert_space)
a_bac

print,idl_validname('1.a bac',/convert_all)
_1_a_bac

②局部变量

pro test_1
  ;print,'idl'
  a=10
end

pro test_var
  test_1
  print,a
end

　　这个语句会报错

③全局变量

pro test_1
  ;print,'idl'
 ;a=10
 defsysv,'!var',10 
end

pro test_var
  test_1
  ;print,a
  print,!var
end

④公共区域

pro test_1
  common comName,var1
  var1=10 
end

pro test_var
  common comName
  test_1
  print,var1
end

2、定义数组

arr=[[1,2,3,3],[1,1,1,1]]
help,arr
print,arr[3,0]

先列后行

①

IDL> arr=indgen(5)
IDL> help,arr
ARR             INT       = Array[5]
IDL> print,arr
       0       1       2       3       4
IDL> print,3*arr
       0       3       6       9      12
IDL> print,3^arr
       1       3       9      27      81
 

等差数列，等比数列

print,arr mod 2

②数组引用

IDL> a=indgen(8)*3
IDL> print,a
       0       3       6       9      12      15      18      21
IDL> print,a[2:4]
       6       9      12
IDL> idx=[3,5]
IDL> print,a[idx]
       9      15
IDL> 

　

IDL> print,a
       0       1       2       3
       4       5       6       7
       8       9      10      11
      12      13      14      15
IDL> print,a[2:3,0:1]
       2       3
       6       7

 

　

IDL> print,a[1:3:2,*]
       1       3
       5       7
       9      11
      13      15
IDL> print,a>5
       5       5       5       5
       5       5       6       7
       8       9      10      11
      12      13      14      15
IDL> 

Result = SIZE( Expression [, /L64] [, /DIMENSIONS | , /FILE_LUN | , /FILE_OFFSET | , /N_DIMENSIONS | , /N_ELEMENTS | , /SNAME, | , /STRUCTURE | , /TNAME | , /TYPE] )

IDL> a=indgen(5,6)
IDL> print,a
       0       1       2       3       4
       5       6       7       8       9
      10      11      12      13      14
      15      16      17      18      19
      20      21      22      23      24
      25      26      27      28      29
IDL> idx=where(a gt 22)
IDL> print,idx
          23          24          25          26          27          28          29
IDL> print,a[idx]
      23      24      25      26      27      28      29
IDL>