python - 添加到地图列表或更新先前添加的地图 aws-dynamodb 的值

Question

我的 dynamodb 中有一个“地图列表”类型的属性。例如 List = [{key1: value1},{key2: value2},{key3:value3},...] 我想用 current_key 更新列表（来自我的 python 脚本）以添加新键或替换值，如果current_key 已经存在。

Answer 1

为了更好地说明下面的代码，我选择将您的代码更改{key1:value1}为字符串。从功能上讲，当您调用该add_to_datalist函数时，应该没有区别。

def add_to_datalist(datalist, key, value):
    check = 0 
#check is needed to ensure the if condition after the for loop can trigger
    for datadict in datalist:
        if key in datadict.keys():
            datadict[key] = value
            check = 1 #turn off check if a key matching is found

    if check == 0:
        datalist.append({key:value})

    return datalist



datalist = [{'key1':'value1'},{'key2':'value2'},{'key3':'value3'}]

key1 = 'key333'
value1 = 'value999'
datalist = add_to_datalist(datalist, key1, value1)
key2 = 'key2'
value2 = 'valueNEW2'
datalist = add_to_datalist(datalist, key2, value2)

print (datalist)
#[{'key1': 'value1'}, {'key2': 'valueNEW2'}, {'key3': 'value3'}, {'key333': 'value999'}]