如何在从json响应中获得两个匹配后中断循环

Question

我只是想知道，在得到1或2个结果之后，是否有可能打破循环，并在相同的条件下设计它的变量。

import json

lookup_dt = "2022-03-09"

r = '{"DBClusterSnapshots": [{"DBClusterSnapshotIdentifier": "snap-1", "DBClusterIdentifier": "aurora-cluster", "SnapshotCreateTime": "2022-03-09", "Engine": "aurora-postgresql", "EngineVersion": "12.7", "SnapshotType": "manual"}, {"DBClusterSnapshotIdentifier": "snap-2", "DBClusterIdentifier": "aurora-cluster", "SnapshotCreateTime": "2022-03-09", "Engine": "aurora-postgresql", "EngineVersion": "12.7", "SnapshotType": "manual"}, {"DBClusterSnapshotIdentifier": "snap-3", "DBClusterIdentifier": "aurora-cluster", "SnapshotCreateTime": "2022-03-09", "Engine": "aurora-postgresql", "EngineVersion": "12.7", "SnapshotType": "manual"}]}'

data = json.loads(r)


snap = [
    d["DBClusterSnapshotIdentifier"]
    for d in response["DBClusterSnapshots"]
    if d['SnapshotCreateTime'].strftime("%Y-%m-%d") == lookup_dt
]

SnapshotId, SnapshotId2,..n = SnapshotId_l[:n]

if SnapshotId :
    print("INFO: Found manual snapshots for requested date: " + str(SnapshotId))
elif: SnapshotId2
    print("INFO: Found manual snapshots for requested date: " + str(SnapshotId2))
else:
    print("ERROR: Snapshot did not find for requested date : " + str(args_lookup_dt))
    exit(1)

假设在if d['SnapshotCreateTime'].strftime("%Y-%m-%d") == lookup_dt条件下，有时可以得到1或更多。日期可能是相同的，但会有一些小数时差。我的用例是:获取一个并分配varaible，如果两个分配给它两个varivales，如果超过两个只是坚持使用onyl 2。

我希望输出结果就像打印出来的一样。

这是可能的还是没有意义的？

Answer 1

可以使用简单的列表理解将所有快照名称放入列表中：

import json

lookup_dt = "2022-03-09"
r = '{"DBClusterSnapshots": [{"DBClusterSnapshotIdentifier": "snap-1", "DBClusterIdentifier": "aurora-cluster", "SnapshotCreateTime": "2022-03-09", "Engine": "aurora-postgresql", "EngineVersion": "12.7", "SnapshotType": "manual"}, {"DBClusterSnapshotIdentifier": "snap-2", "DBClusterIdentifier": "aurora-cluster", "SnapshotCreateTime": "2022-03-09", "Engine": "aurora-postgresql", "EngineVersion": "12.7", "SnapshotType": "manual"}, {"DBClusterSnapshotIdentifier": "snap-3", "DBClusterIdentifier": "aurora-cluster", "SnapshotCreateTime": "2022-03-09", "Engine": "aurora-postgresql", "EngineVersion": "12.7", "SnapshotType": "manual"}]}'
data = json.loads(r)

snaps = [
    d["DBClusterSnapshotIdentifier"]
    for d in data["DBClusterSnapshots"]
    if d["SnapshotCreateTime"] == lookup_dt
]
print(snaps)  # ['snap-1', 'snap-2', 'snap-3']

如果您想将前两个变量分配给变量snap1和snap2，您可以这样做：

snap1, snap2 = snaps[:2]

但在实践中，您可能会发现只按原样使用snaps列表就更容易了。

(编辑)每个注释，如果希望创建时间为快照ID，则如下所示：

snap_times = {
    d["DBClusterSnapshotIdentifier"]: d["SnapshotCreateTime"]
    for d in data["DBClusterSnapshots"]
    if d["SnapshotCreateTime"] == lookup_dt
}

print(snap_times)
# {'snap-1': '2022-03-09', 'snap-2': '2022-03-09', 'snap-3': '2022-03-09'}

注意，由于我们使用lookup_dt进行了过滤，所有创建时间都将等于lookup_dt。如果不想这样做，只需删除if d["SnapshotCreateTime"] == lookup_dt行即可。