我有一个来自API的json
"nutrient_value": [
{
"Calcium": [
"29.16",
"mg",
"Red",
"0.00102858984",
"ounce"
]
},
{
"Choline": [
"118.97",
"mg",
"Red",
"0.00419654778",
"ounce"
]
},
{
"Copper": [
"0.12",
"mg",
"Red",
"0.00000423288",
"ounce"
]
},
{
"Crude fat": [
"29.16",
"g",
"Green",
"1.02858984",
"ounce"
]
},
{
"Folate": [
"11.66",
"mcg",
"Red",
"0.00000041129484",
"ounce"
]
},
{
"Iodine": [
"0.0",
"mcg",
"Red",
"0.0",
"ounce"
]
},
{
"Iron": [
"4.08",
"mg",
"Yellow",
"0.00014391792",
"ounce"
]
},
{
"Magnesium": [
"34.99",
"mg",
"Green",
"0.00123423726",
"ounce"
]
},
{
"Manganese": [
"0.02",
"mg",
"Red",
"0.00000070548",
"ounce"
]
},
{
"Niacin (B3)": [
"9.04",
"mg",
"Green",
"0.00031887696",
"ounce"
]
},
{
"Omega-3 excl. ALA and SDA": [
"0.02",
"g",
"Red",
"0.00070548",
"ounce"
]
},
{
"Omega-6": [
"0.02",
"g",
"Red",
"0.00070548",
"ounce"
]
},
{
"Pantothenic acid (B5)": [
"1.07",
"mg",
"Red",
"0.00003774318",
"ounce"
]
},
{
"Phosphorus": [
"332.42",
"mg",
"Red",
"0.01172578308",
"ounce"
]
},
{
"Potassium": [
"573.48",
"mg",
"Yellow",
"0.02022893352",
"ounce"
]
},
{
"Protein": [
"36.94",
"g",
"Green",
"1.30302156",
"ounce"
]
},
{
"Riboflavin (B2)": [
"0.29",
"mg",
"Red",
"0.00001022946",
"ounce"
]
},
{
"Selenium": [
"30.72",
"mcg",
"Red",
"0.00000108361728",
"ounce"
]
},
{
"Sodium (Na)": [
"128.3",
"mg",
"Green",
"0.0045256542",
"ounce"
]
},
{
"Thiamin (B1)": [
"0.08",
"mg",
"Red",
"0.00000282192",
"ounce"
]
},
{
"Vitamin A": [
"8.16",
"mcg",
"Red",
"0.00000028783584",
"ounce"
]
},
{
"Vitamin C": [
"0.0",
"mg",
"Green",
"0.0",
"ounce"
]
},
{
"Vitamin D": [
"0.19",
"mcg",
"Red",
"0.00000000670206",
"ounce"
]
},
{
"Vitamin E": [
"0.33",
"mg",
"Red",
"0.00001164042",
"ounce"
]
},
{
"Zinc (Zn)": [
"8.71",
"mg",
"Red",
"0.00030723654",
"ounce"
]
},
{
"Calories": [
"417.96",
"cal",
null,
"N/A",
"ounce"
]
},
{
"Omega-3/6 ratio": [
"0.65",
"ratio",
"Green",
"N/A",
"ounce"
]
},
{
"Calcium/Phosphorus ratio": [
"0.06",
"ratio",
"Red",
"N/A",
"ounce"
]
}
],
从上述json即时消息中将其解码为此
var resJson = json.decode(res);
MPD.Result _mealPlan = MPD.Result.fromJson(resJson["result"]);
///
factory Result.fromJson(Map<String, dynamic> json) => Result(
id: json["id"],
....
nutrientValue: List<NutrientValue>.from(json["nutrient_value"].map((x) => NutrientValue.fromJson(x))),
....
);
"nutrient_value": []
在营养值数组中，对于每个项目，我需要检查给定键（例如：“钙”）是否存在，如果存在，则获取该键的索引[0]和[2]的值：
Example key "Calcium" exists and
valueCalcium = value of index[0]
colorCalcium = value of index[2]
"nutrient_value": [
{
"Calcium": [
"29.16",
"mg",
"Red",
"0.00102858984",
"ounce"
}
我该怎么做呢？
我已经尝试过了
_mealPlan.nutrientValue.forEach((element) {
if(element.calcium.isNotEmpty){
valCalcium = element.calcium[0];
print(valCalcium);//_mealPlan.nutrientValue[0].calcium[0];
calciumClr = element.calcium[2];
print(calciumClr);
}
});
但这似乎不是正确的方法。
我在代码的后面部分中使用了这两个索引值中的每一个。
答案 0 :(得分：0)
您可以这样做：
void main() {
Map<String, dynamic> data = {
"success": true,
"result": {
"id": 7,
"daily_allowance_actual_percentage": {
"Bone": [0, "Red"],
"Muscle Meat": [100, "Red"]
},
"daily_calories_from_this_meal_plan": "417.96",
"imperial_weight_of_one_meal": "2.2857552",
"meal_ingredients_would_make": 3,
"meals_per_day": 3,
"nutrient_value": [
{
"Calcium": ["29.16", "mg", "Red", "0.00102858984", "ounce"]
},
{
"Choline": ["118.97", "mg", "Red", "0.00419654778", "ounce"]
},
{
"Copper": ["0.12", "mg", "Red", "0.00000423288", "ounce"]
},
{
"Crude fat": ["29.16", "g", "Green", "1.02858984", "ounce"]
},
{
"Folate": ["11.66", "mcg", "Red", "0.00000041129484", "ounce"]
},
{
"Iodine": ["0.0", "mcg", "Red", "0.0", "ounce"]
},
{
"Iron": ["4.08", "mg", "Yellow", "0.00014391792", "ounce"]
},
{
"Magnesium": ["34.99", "mg", "Green", "0.00123423726", "ounce"]
},
{
"Manganese": ["0.02", "mg", "Red", "0.00000070548", "ounce"]
},
{
"Niacin (B3)": ["9.04", "mg", "Green", "0.00031887696", "ounce"]
},
{
"Omega-3 excl. ALA and SDA": [
"0.02",
"g",
"Red",
"0.00070548",
"ounce"
]
},
{
"Omega-6": ["0.02", "g", "Red", "0.00070548", "ounce"]
},
{
"Pantothenic acid (B5)": [
"1.07",
"mg",
"Red",
"0.00003774318",
"ounce"
]
},
{
"Phosphorus": ["332.42", "mg", "Red", "0.01172578308", "ounce"]
},
{
"Potassium": ["573.48", "mg", "Yellow", "0.02022893352", "ounce"]
},
{
"Protein": ["36.94", "g", "Green", "1.30302156", "ounce"]
},
{
"Riboflavin (B2)": ["0.29", "mg", "Red", "0.00001022946", "ounce"]
},
{
"Selenium": ["30.72", "mcg", "Red", "0.00000108361728", "ounce"]
},
{
"Sodium (Na)": ["128.3", "mg", "Green", "0.0045256542", "ounce"]
},
{
"Thiamin (B1)": ["0.08", "mg", "Red", "0.00000282192", "ounce"]
},
{
"Vitamin A": ["8.16", "mcg", "Red", "0.00000028783584", "ounce"]
},
{
"Vitamin C": ["0.0", "mg", "Green", "0.0", "ounce"]
},
{
"Vitamin D": ["0.19", "mcg", "Red", "0.00000000670206", "ounce"]
},
{
"Vitamin E": ["0.33", "mg", "Red", "0.00001164042", "ounce"]
},
{
"Zinc (Zn)": ["8.71", "mg", "Red", "0.00030723654", "ounce"]
},
{
"Calories": ["417.96", "cal", null, "N/A", "ounce"]
},
{
"Omega-3/6 ratio": ["0.65", "ratio", "Green", "N/A", "ounce"]
},
{
"Calcium/Phosphorus ratio": ["0.06", "ratio", "Red", "N/A", "ounce"]
}
],
"pet_name": "tim",
"show_weight_of_balanced_meal": true,
"suggestion": {
"add_food": {
"Red": [
{
"Calcium": ["Amaranth, grain, whole, uncooked", "Apple, dried"]
},
{
"Copper": ["Amaranth, grain, whole, uncooked", "Apple, dried"]
},
{
"Folate": [
"Amaranth, grain, whole, uncooked",
"Apple, fuji, unpeeled, raw"
]
},
{
"Iodine": ["Amaranth, grain, whole, uncooked", "Apricot, dried"]
},
{
"Manganese": ["Amaranth, grain, whole, uncooked", "Apple, dried"]
},
{
"Omega-3 excl. ALA and SDA": ["Bass, fillet, raw", "Beef Brain"]
},
{
"Omega-6": ["Amaranth, grain, whole, uncooked", "Avocado, raw"]
},
{
"Pantothenic acid (B5)": [
"Amaranth, grain, whole, uncooked",
"Apple, dried"
]
},
{
"Riboflavin (B2)": [
"Amaranth, grain, whole, uncooked",
"Apple, fuji, unpeeled, raw"
]
},
{
"Thiamin (B1)": [
"Amaranth, grain, whole, uncooked",
"Apple, fuji, unpeeled, raw"
]
},
{
"Vitamin A": ["Bean, edamame, from frozen, cooked", "Beef Brain"]
},
{
"Vitamin D": ["Beef kidney, raw", "Beef liver, raw"]
},
{
"Vitamin E": ["Amaranth, grain, whole, uncooked", "Apple, dried"]
},
{
"Crude fat": ["Amaranth, grain, whole, uncooked", "Apple, dried"]
},
{
"Magnesium": ["Amaranth, grain, whole, uncooked", "Apple, dried"]
},
{
"Niacin (B3)": [
"Apple, fuji, unpeeled, raw",
"Apple, golden delicious, unpeeled, raw"
]
},
{
"Protein": ["Amaranth, grain, whole, uncooked", "Apple, dried"]
},
{
"Sodium (Na)": [
"Amaranth, grain, whole, uncooked",
"Apple, dried"
]
}
],
"Yellow": []
},
"remove_food": {
"Red": [
{
"Choline": ["Beef, mince, 15% fat, raw"]
},
{
"Phosphorus": ["Beef, mince, 15% fat, raw"]
},
{
"Selenium": ["Beef, mince, 15% fat, raw"]
},
{
"Zinc (Zn)": ["Beef, mince, 15% fat, raw"]
}
],
"Yellow": [
{
"Iron": ["Beef, mince, 15% fat, raw"]
},
{
"Potassium": ["Beef, mince, 15% fat, raw"]
}
]
}
},
"total_calories_in_a_meal_plan": 645,
"total_imperial_weight_of_a_meal_plan": 10.5822,
"total_weight_of_a_meal_plan": 300,
"weight_of_one_meal": "64.8",
"feeding_plan_details": [
{
"id": 23,
"imperial_quantity": 10.5822,
"quantity": 300,
"food": {
"id": 6,
"bone_percentage": 0,
"name": "Beef, mince, 15% fat, raw"
}
}
]
}
};
List<Map<String, dynamic>> nutrientValue = data["result"]["nutrient_value"];
List<Map<String, dynamic>> filteredData = nutrientValue
.where((Map<String, dynamic> element) =>
element.keys.toList()[0] == "Calcium")
.toList();
for (Map<String, dynamic> i in filteredData) {
print("${i[i.keys.toList()[0]][0]} && ${i[i.keys.toList()[0]][2]}");
}
}