英文:
Iterating over a JSON array
问题
以下是您提供的代码的翻译部分：
我有以下的JSON数组;
```json
"json_array": [
{
"key": "k1",
"value": "v1"
},
{
"key": "k2",
"value": "v2"
}
]
需要将值列出为v1,v2。
目前，我能够分别列出键和值，但不能分开列出:
k1:v1
k2:v2
或
k1
k2
或
v1
v2
我尝试获得类似于:
v1,v2 但我不确定如何进行迭代，就像如果我只需要打印一个值，要么是v1要么是v2。如果有人能帮我解决Python 3中的逻辑，那将非常好。
编辑后的代码:
json_array = [
[
{
"key": "k1",
"value": "v1"
},
{
"key": "k1",
"value": "v2"
}
],
[
{
"key": "k1",
"value": "v3"
},
{
"key": "k2",
"value": "v4"
}
],
[
{
"key": "k2",
"value": "v5"
},
{
"key": "k3",
"value": "v6"
}
]
]
itemcount = 0
for item in json_array:
print(item)
values = []
for kv in item:
if 'value' in kv:
values.append(kv['value'])
print(', '.join([kv['key']] + values))
输出:
[{'key': 'k1', 'value': 'v1'}, {'key': 'k1', 'value': 'v2'}]
k1, v1, v2
[{'key': 'k1', 'value': 'v3'}, {'key': 'k2', 'value': 'v4'}]
k2, v3, v4
[{'key': 'k2', 'value': 'v5'}, {'key': 'k3', 'value': 'v6'}]
k3, v5, v6
期望输出:
k1, v1, v2, v3
k2, v4, v5
k3, v6
如果您需要进一步的帮助，请告诉我。
<details>
<summary>英文:</summary>
I have the following JSON array;
"json_array": [
{
"key": "k1",
"value": "v1"
},
{
"key": "k2",
"value": "v2"
}
]
Need to list values as v1,v2.
Currently, I am able to list the keys and values separately as follows, but as a whole, not separately:
k1:v1
k2:v2
or
k1
k2
or
v1
v2
I was trying to get something like:
v1,v2 but I'm not sure how to go about the iteration, like if I just need to print one value either v1 or v2. If someone could help me with the logic in Python 3, that would be really great.
Edited code:
json_array = [
[
{
"key": "k1",
"value": "v1"
},
{
"key": "k1",
"value": "v2"
}
],
[
{
"key": "k1",
"value": "v3"
},
{
"key": "k2",
"value": "v4"
}
],
[
{
"key": "k2",
"value": "v5"
},
{
"key": "k3",
"value": "v6"
}
]
]
itemcount = 0
for item in json_array:
print(item)
values = []
for kv in item:
if 'value' in kv:
values.append(kv['value'])
print(', '.join([kv['key']] + values))
Output:
[{'key': 'k1', 'value': 'v1'}, {'key': 'k1', 'value': 'v2'}]
k1, v1, v2
[{'key': 'k1', 'value': 'v3'}, {'key': 'k2', 'value': 'v4'}]
k2, v3, v4
[{'key': 'k2', 'value': 'v5'}, {'key': 'k3', 'value': 'v6'}]
k3, v5, v6
Expected output:
k1, v1, v2, v3
k2, v4, v5
k3, v6
</details>
# 答案1
**得分**: 1
这是您要翻译的代码部分：
```python
json_array = [
{
"key": "k1",
"value": "v1"
},
{
"key": "k2",
"value": "v2"
}
]
itemcount = 0
values = []
for item in json_array:
print(f'Item => {itemcount}')
itemcount += 1
if 'value' in item:
print(f"Value => {item['value']}")
values.append(item['value'])
print(', '.join(values))
这将为您提供以下输出：
Item => 0
Value => v1
Item => 1
Value => v2
v1, v2
如果您只想要v1, v2作为输出，可以使用以下代码：
values = []
for item in json_array:
if 'value' in item:
values.append(item['value'])
print(', '.join(values))
我们在这里的操作是遍历列表中的每个项。每个项都是一个字典。我们询问字典是否有'value'属性。如果有，我们将其添加到列表中。
最后，我们使用', '分隔符连接列表。
您可以根据需要修改这个代码来获得所需的输出。希望这能帮助您入门。
英文:
You could do something like this:
json_array = [
{
"key": "k1",
"value": "v1"
},
{
"key": "k2",
"value": "v2"
}
]
itemcount = 0
values = []
for item in json_array:
print(f'Item => {itemcount}')
itemcount += 1
if 'value' in item:
print(f"Value => {item['value']}")
values.append(item['value'])
print(', '.join(values))
That'll give you output like this:
Item => 0
Value => v1
Item => 1
Value => v2
v1, v2
If you just wanted v1, v2 as the output, you could just do this:
values = []
for item in json_array:
if 'value' in item:
values.append(item['value'])
print(', '.join(values))
What are we doing here?
We loop through each item in the list. Each item is a dictionary. We ask the dictionary if it has 'value' property. If it has, then we add it to a list.
Finally, we join the list with ', ' separator.
You can morph this to whatever output you desire. Hope this gets you started.
EDIT
What if you have an nested lists/arrays?
json_array = [
[
{
"key": "k1",
"value": "v1"
},
{
"key": "k2",
"value": "v2"
}
],
[
{
"key": "k1",
"value": "v3"
},
{
"key": "k2",
"value": "v4"
}
]
]
itemcount = 0
values = []
for item in json_array:
print(f'Item => {itemcount}')
itemcount += 1
for kv in item:
if 'value' in kv:
print(f"Value => {kv['value']}")
values.append(kv['value'])
print(', '.join(values))
The result will be:
Item => 0
Value => v1
Value => v2
Item => 1
Value => v3
Value => v4
v1, v2, v3, v4
EDIT 2
If you want v1, v2 in one line and v3, v4 in another line
You could use a slightly modified code to print v1, v2 in one line and v3, v4 in another line.
json_array = [
[
{
"key": "k1",
"value": "v1"
},
{
"key": "k2",
"value": "v2"
}
],
[
{
"key": "k1",
"value": "v3"
},
{
"key": "k2",
"value": "v4"
}
]
]
itemcount = 0
for item in json_array:
print(f'Item => {itemcount}')
itemcount += 1
values = []
for kv in item:
if 'value' in kv:
print(f"Value => {kv['value']}")
values.append(kv['value'])
print(', '.join(values))
The result will be:
Item => 0
Value => v1
Value => v2
v1, v2
Item => 1
Value => v3
Value => v4
v3, v4
It seems like OP has figured this out already; great job.
EDIT 3
What if we want key, value1, value2, ...?
json_array = [
[
{
"key": "k1",
"value": "v1"
},
{
"key": "k1",
"value": "v2"
}
],
[
{
"key": "k1",
"value": "v3"
},
{
"key": "k2",
"value": "v4"
}
],
[
{
"key": "k2",
"value": "v5"
},
{
"key": "k3",
"value": "v6"
}
]
]
itemcount = 0
values = {}
for item in json_array:
itemcount += 1
for kv in item:
if kv['key'] not in values:
values[kv['key']] = []
values[kv['key']].append(kv['value'])
for key in values:
print(key + ', ' + ', '.join(values[key]))
will result in:
k1, v1, v2, v3
k2, v4, v5
k3, v6
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