Question

这是我的例子：

dictlist = [{'first': 'James', 'last': 'Joule'}, 
            {'first': 'James','last': 'Watt'},
            {'first': 'Christian','last': 'Doppler'}]

我想知道姓氏。如果这是在模型中，代码将是：

getdata = Name.objects.filter(name="Christian")
getLastName = getdata.last

我会得到"Doppler"。

Answer 1

这是一个非常简单的列表理解解决方案：

>>> dictlist = [{'first': 'James', 'last': 'Joule'}, {'first': 'James','last': 'Watt'},{'first': 'Christian','last': 'Doppler'}]
>>> [x['last'] for x in dictlist if x['first'] == 'Christian']
['Doppler']

Answer 2

首先，我们可以有一个仅使用内置 python filter method 的简单脚本，这可能已经足够了：

fl = list(filter(lambda x: x['first'] == 'Christian', dictlist))

# you can't use `.property` because this is a dictionary, not a object
fl[0]['last']
# returns Doppler

我意识到你的例子是一个 Django 代码，所以如果你想让它更动态，以便你能够通过字典中的任何键进行过滤：

def dict_filter(dictlist: list, key: str, value: str) -> list:
    return list(filter(lambda x: x.get(key) == value, dictlist))

dict_filter(dictlist, 'first', 'Christian')
# similar to django's filter method returns a queryset, this returns a list:
# [{'first': 'Christian', 'last': 'Doppler'}]

dict_filter(dictlist, 'last', 'Doppler')
# returns [{'first': 'Christian', 'last': 'Doppler'}]

dict_filter(dictlist, 'last', 'notfound')
# returns []

以及使用 python filter method 创建与 Django 的 QuerySet.get 方法类似的函数的示例：

def dict_get(dictlist: list, key: str, value: str) -> list:
    ret = list(filter(lambda x: x.get(key) == value, dictlist))
    if len(ret) == 0:
        raise Exception('Not Found')
    if len(ret) > 1:
        raise Exception(f'Found more than 1 object with {key}={value}')
    return ret[0]

dict_get(dictlist, 'first', 'Christian')
# returns {'first': 'Christian', 'last': 'Doppler'}
    
dict_get(dictlist, 'first', 'Christians')
# raises Exception: Not Found

dict_get(dictlist, 'first', 'James')
# raises Exception: Found more than 1 object with first=James

希望对你有帮助！

Answer 3

这样的事情应该有效

last_name = ''

for d in dictList:
  if d['first'] == 'Christian':
    last_name = d['last']
    break

Answer 4

var express = require('express');
var router = express.Router();
var request = require('request');
var qs = require('querystring');
var configAuth = require('../config/auth');

var authorization_url_site = configAuth.iHealthAuth.authorizationSite;
var authorization_url_params = {
    response_type : 'code',
    client_id: configAuth.iHealthAuth.clientID,
    redirect_uri: configAuth.iHealthAuth.callbackURL,
    APIName : configAuth.iHealthAuth.APIName
};
var authorization_uri = authorization_url_site + '?' + qs.stringify(authorization_url_params);

var token_url_site = configAuth.iHealthAuth.tokenSite;
var token_url_params = {
    grant_type : 'authorization_code',
    client_id: configAuth.iHealthAuth.clientID,
    client_secret: configAuth.iHealthAuth.clientSecret,
    redirect_uri: configAuth.iHealthAuth.callbackURL,
    code: req.query.code
};
var token_uri = token_url_site + '?' + qs.stringify(token_url_params);

// Initial page redirecting to the login page
router.route('/auth')
    .get(function (req, res) {
            res.redirect(authorization_uri);
    });

// Callback service parsing the authorization token and asking for the access token
router.route('/')
    .get(function(req, res) {

        request(token_uri, function(err, response, body) {
                if(err) {
                    throw err;
                } else {
                    var data = JSON.parse(body);
                    // save token to database or file
                    saveToken(data);
                }
            });
        });
    });

module.exports = router;

结果var owner = "..."; var repository = "..."; var gitHubClient = new GitHubClient( new ProductHeaderValue("MyApp"), new InMemoryCredentialStore(new Credentials("GitHubToken"))); var pullRequest = await gitHubClient.PullRequest.Get(owner, repository, pullRequestNumber); Console.WriteLine("Summarising Pull Request #{0} - {1}", pullRequest.Number, pullRequest.Title); var commits = new List<GitHubCommit>(); var moreToGet = true; var headSha = pullRequest.Head.Sha; while (moreToGet) { var comparison = await gitHubClient.Repository.Commits.Compare( owner, repository, pullRequest.Base.Sha, headSha); // Because we're working backwards from the head towards the base, but the oldest commits are at the start of the list commits.InsertRange(0, comparison.Commits); moreToGet = comparison.Commits.Count == 250; if (moreToGet) { headSha = commits.First().Sha; } }仅包含：

dictlist = [{'first': 'James', 'last': 'Joule'}, {'first': 'James','last': 'Watt'},{'first': 'Christian','last': 'Doppler'}]
the_jameses = [d for d in dictlist if d['first'] == 'James']

Answer 5

我有时喜欢使用next：

next((d['last'] for d in dictlist if d['first'] == 'Christian'), None)
# 'Doppler'

第一个参数是一个迭代器，第二个（可选）参数是在找不到匹配项的情况下返回的默认值。

注意：这只会返回第一个匹配结果。因此，如果您希望有多个与“查询”匹配的记录，那就不好了。

过滤词典列表

6 个答案: