如何在字典中查找特定值并正确 return 它们

Question

所以我有一个字典列表字典 (lst)，我试图遍历它，比较值，然后 return 适当的值。

我有以下代码来检索从命令行给出的 2 个参数，通过字典条目比较它们，return 适当的值：

def get_attribute_number(cmd1, cmd2, lst):

    app_name = cmd1
    attribute = cmd2
    for name in lst: #lst is a dictionary
        if name["description"] == app_name:
            print(int(name[attribute]))

get_attribute_number(cmd1=sys.argv[1], cmd2=sys.argv[2], lst=data_list)

但是，我的程序没有 returning 任何东西。例如，如果我提供 cmd 行参数 python3 program.py [NAME] [ATTRIBUTE]，它应该查询上述数据，直到找到名称的匹配项，并且 return 其请求的属性为整数。任何人都可以就为什么我不能 print(int(name[attribute])) 对应 napp_name 提出建议吗？

Answer 1

我稍微更改了您的代码以对用户更友好：

import sys

data_list = [{'{#Status}': "['failed']", '{#DESCRIPTION}': "['kytos/kytos']", '{#PASSED}': '316', '{#FAILED}': '1', '{#WARNING}': '204', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['success']", '{#DESCRIPTION}': "['kytos/python-openflow']", '{#PASSED}': '400', '{#FAILED}': 0, '{#WARNING}': 0, '{#SKIPPED}': '40', '{#XFAILED}': '1'},
{'{#Status}': "['success']", '{#DESCRIPTION}': "['kytos/of_core']", '{#PASSED}': '49', '{#FAILED}': 0, '{#WARNING}': '39', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['failed']", '{#DESCRIPTION}': "['kytos/kytos-utils']", '{#PASSED}': '102', '{#FAILED}': '2', '{#WARNING}': 0, '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['success']", '{#DESCRIPTION}': "['kytos/mef_eline']", '{#PASSED}': '102', '{#FAILED}': 0, '{#WARNING}': '88', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['success']", '{#DESCRIPTION}': "['kytos/flow_manager']", '{#PASSED}': '36', '{#FAILED}': 0, '{#WARNING}': '22', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['success']", '{#DESCRIPTION}': "['kytos/topology']", '{#PASSED}': '58', '{#FAILED}': 0, '{#WARNING}': '56', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['success']", '{#DESCRIPTION}': "['kytos/kronos']", '{#PASSED}': '61', '{#FAILED}': 0, '{#WARNING}': '21', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['failed']", '{#DESCRIPTION}': "['kytos/pathfinder']", '{#PASSED}': 0, '{#FAILED}': 0, '{#WARNING}': 0, '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['failed']", '{#DESCRIPTION}': "['kytos/status']", '{#PASSED}': '81', '{#FAILED}': 0, '{#WARNING}': '1', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['success']", '{#DESCRIPTION}': "['kytos/of_l2ls']", '{#PASSED}': '7', '{#FAILED}': 0, '{#WARNING}': '7', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['success']", '{#DESCRIPTION}': "['kytos/of_lldp']", '{#PASSED}': '17', '{#FAILED}': 0, '{#WARNING}': '17', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['success']", '{#DESCRIPTION}': "['kytos/maintenance']", '{#PASSED}': '28', '{#FAILED}': 0, '{#WARNING}': '28', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['failed']", '{#DESCRIPTION}': "['kytos/storehouse']", '{#PASSED}': '63', '{#FAILED}': '1', '{#WARNING}': '32', '{#SKIPPED}': 0, '{#XFAILED}': 0},
{'{#Status}': "['failed']", '{#DESCRIPTION}': "['kytos/kytos-end-to-end-tester']", '{#PASSED}': 0, '{#FAILED}': 0, '{#WARNING}': 0, '{#SKIPPED}': 0, '{#XFAILED}': 0}]

def get_attribute_number(cmd1, cmd2, lst):
    """For each attribute under a napp, retrieve that attribute as a NUMBER"""
    napp_name = cmd1
    attribute_name = cmd2
    for napp in lst: #lst is a dictionary
        if napp_name in napp["{#DESCRIPTION}"]: # change happened here
            print(napp)
            print(int(napp[attribute_name]))

get_attribute_number(sys.argv[1], sys.argv[2], data_list)

基本上他们只需要输入子字符串就可以得到一些结果，所以这个：

python tt.py 'kytos/kytos' {#SKIPPED}

只输出需要的数据：

{'{#Status}': "['failed']", '{#DESCRIPTION}': "['kytos/kytos']", '{#PASSED}': '316', '{#FAILED}': '1', '{#WARNING}': '204', '{#SKIPPED}': 0, '{#XFAILED}': 0}
0

Answer 2

要回答有关转换为字符串的问题：您可以尝试评估将为您提供列表的表达式；如果格式始终相同，您还可以使用正则表达式：

import ast
ast.literal_eval(napp["{#DESCRIPTION}"])[0]

所以在你的情况下：

import ast
def get_attribute_number(cmd1, cmd2, lst):
    """For each attribute under a napp, retrieve that attribute as a NUMBER"""
    napp_name = cmd1
    attribute_name = cmd2
    for napp in lst: #lst is a dictionary
        if ast.literal_eval(napp["{#DESCRIPTION}"])[0] == napp_name:
            print(int(napp[attribute_name]))

如何在字典中查找特定值并正确 return 它们

How to look for specific values in a dictionary and return them properly

python

iteration

parsing

dictionary

dictionary-comprehension