Google Earth Engine（gee）中的Dictionary

怼烎@ 2021-07-25 13:32 440阅读 0赞

用法类似js中的对象，key/value

## get()、keys() ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70][]

var user=ee.Dictionary({
      username:"lijiang",
      password:123,
      more:[1,2,3],
      pi:Math.PI,
      age:20+2
    })
    
    print("user:",user)
    print("user.username",user.get("username"))
    print("user.get('pi')",user.get("pi"))
    
    print("user.keys()",user.keys())
    print("user.values()",user.values())
    print(user.get('age'))

## contains()、values()、set() ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 1][]

var user=ee.Dictionary({
      username:"lijiang",
      password:123,
      more:[1,2,3],
      pi:Math.PI,
      age:20+2
    })
    
    var set_password=user.set("password",123456)
    
    print(user)
    
    print(set_password.values(['username','password']))
    print(user.values(['username','password']))
    
    print(user.contains("username"))//true
    print(user.contains("a"))//false

## 字典的合并：Dictionary.combine() ##

Key相同的情况，此时如果在.combine( , )命令中指定第二个参数为true，那么这时在合并的字典中就会将重复的内容保留为第二个变量的值。相反的，如果将第二个参数指定为false，那么合并字典中的重复内容就是第一个字典的值![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwMzIzMjU2_size_16_color_FFFFFF_t_70 2][]

var dic1=ee.Dictionary({name:"xiaoming",age:18,sex:"男"})
    var dic2=ee.Dictionary({name:"xiaohong",age:20,height:170})
    
    print(dic1.combine(dic2))//默认为true
    print(dic1.combine(dic2,true))//为true时，以dic2为准
    print(dic1.combine(dic2,false))//为false时，以dic1为准

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