英文:
R: Correctly Writing and Converting Dates in UTC Format
问题
我正在尝试学习如何使用Reddit API（https://www.reddit.com/prefs/apps）。
我注册了一个账户/API - 我想检索在2020年3月1日至2020年3月2日期间发布的包含单词"covid"的100条评论。
使用API的文档（https://www.reddit.com/dev/api/），我运行了以下R代码。
首先，我注册了API：
library(httr)library(jsonlite)response <- POST("https://www.reddit.com/api/v1/access_token",authenticate('****', '***'),user_agent("some_name"),body = list(grant_type="password",username="aaaaaa",password="bbbbbbb"))access_token_json <- rawToChar(response$content)access_token_content <- fromJSON(access_token_json)access_token <- access_token_content$access_tokenaccess_tokenurl <- "https://oauth.reddit.com/LISTING" # 尝试 api/v1/meauthorization_bearer <- paste("Bearer ", access_token, sep="")result <- GET(url,user_agent("some_name"),add_headers(Authorization = authorization_bearer))
接下来，我尝试发起请求：
# 设置开始和结束时间start_time <- as.numeric(as.POSIXct("2020-03-01 16:52:00", tz = "UTC"))end_time <- as.numeric(as.POSIXct("2020-03-02 13:52:00", tz = "UTC"))# 设置查询参数query_params <- list(limit = 100,q = "covid",#subreddit = "news", ##author = "some_author", #after = start_time,before = end_time)# 进行API请求response <- GET(url, query = query_params, add_headers(Authorization = authorization_header, `User-Agent` = user_agent_string))# 提取响应response_json <- rawToChar(response$content)response_content <- fromJSON(response_json)# 提取相关字段final_result <- data.frame(title = response_content$data$children$data$title,subreddit = response_content$data$children$data$subreddit,author = response_content$data$children$data$author,created_utc = as.POSIXct(response_content$data$children$data$created_utc, origin = "1970-01-01", tz = "UTC"),permalink = paste0("https://www.reddit.com", response_content$data$children$data$permalink))
当我查看结果时：
> head(final_result)title subreddit author created_utc1 COVID-19 is a leading cause of death in children and young people in the United States science thebelsnickle1991 2023-01-30 16:27:212 I thought Covid was a thing of the past.. double vaccinated wicked sick mildlyinfuriating Northeast4life 2023-02-19 00:52:033 ‘People aren’t taking this seriously’: experts say US Covid surge is big risk news ttkciar 2023-01-15 17:25:12
正如我们在这里看到的，日期不在指定的日期范围内。
我认为问题可能是我没有正确地转换日期，所以我查看了原始的UTC日期：
> final_result$created_utc[1] 1675096041 1676767923 1673803512 1671022066 1674220458
但是这些日期似乎不对应我在2020年3月想要的日期（https://www.epochconverter.com/）。
我是不是没有正确地写日期 - 请问有人能帮我修复这个吗？
谢谢！
英文:
I am trying to learn how to use the Reddit API (https://www.reddit.com/prefs/apps).
I registered for an account/API - I want to retrieve 100 comments containing the word "covid" posted between March-01-2020 and March-02-2020.
Using the documentation from the API (https://www.reddit.com/dev/api/), I ran the following R code.
First, I registered the API:
library(httr)library(jsonlite)response <- POST("https://www.reddit.com/api/v1/access_token",authenticate('****', '***'),user_agent("some_name"),body = list(grant_type="password",username="aaaaaa",password="bbbbbbb"))access_token_json <- rawToChar(response$content)access_token_content <- fromJSON(access_token_json)access_token <- access_token_content$access_tokenaccess_tokenurl <- "https://oauth.reddit.com/LISTING" # try api/v1/meauthorization_bearer <- paste("Bearer ", access_token, sep="")result <- GET(url,user_agent("some_name"),add_headers(Authorization = authorization_bearer))
Next, I tried to make a request:
# Set start and end timesstart_time <- as.numeric(as.POSIXct("2020-03-01 16:52:00", tz = "UTC"))end_time <- as.numeric(as.POSIXct("2020-03-02 13:52:00", tz = "UTC"))# Set query parametersquery_params <- list(limit = 100,q = "covid",#subreddit = "news", ##author = "some_author", #after = start_time,before = end_time)# Make the API requestresponse <- GET(url, query = query_params, add_headers(Authorization = authorization_header, `User-Agent` = user_agent_string))# Extract the responseresponse_json <- rawToChar(response$content)response_content <- fromJSON(response_json)# Extract the relevant fieldsfinal_result <- data.frame(title = response_content$data$children$data$title,subreddit = response_content$data$children$data$subreddit,author = response_content$data$children$data$author,created_utc = as.POSIXct(response_content$data$children$data$created_utc, origin = "1970-01-01", tz = "UTC"),permalink = paste0("https://www.reddit.com", response_content$data$children$data$permalink))
When I look at the results:
> head(final_result)title subreddit author created_utc1 COVID-19 is a leading cause of death in children and young people in the United States science thebelsnickle1991 2023-01-30 16:27:212 I thought Covid was a thing of the past.. double vaccinated wicked sick mildlyinfuriating Northeast4life 2023-02-19 00:52:033 ‘People aren’t taking this seriously’: experts say US Covid surge is big risk news ttkciar 2023-01-15 17:25:12
As we can see here, the dates are not between the specified dates.
I thought the problem is that maybe I am not converting the date properly, so I looked at the raw UTC dates :
> final_result$created_utc[1] 1675096041 1676767923 1673803512 1671022066 1674220458
But these dates do not seem to correspond to the dates I wanted in March 2020 (https://www.epochconverter.com/).
Am I not writing the dates correctly - can someone please show me how to fix this?
Thanks!
答案1
得分: 2
尝试使用as.character()函数将开始和结束字符串转换为它们的Unix时间戳：
# 设置开始和结束时间start_time <- as.character(as.POSIXct("2020-03-01 00:00:00", tz = "UTC"))end_time <- as.character(as.POSIXct("2020-03-02 23:59:59", tz = "UTC"))
英文:
Try converting the start and end strings to their Unix timestamps with the as.character() function:
# Set start and end timesstart_time <- as.character(as.POSIXct("2020-03-01 00:00:00", tz = "UTC"))end_time <- as.character(as.POSIXct("2020-03-02 23:59:59", tz = "UTC"))
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