The requirement is to extract data from openweathermap using API, Here is the code I use to extract for more than one city,

# Get forecast data for a given city list
get_weather_forecaset_by_cities <- function(city_names){
     df <- data.frame()
     for (city_name in city_names){
         # Forecast API URL
           forecast_url <- 'https://api.openweathermap.org/data/2.5/forecast'
           # Create query parameters
             forecast_query <- list(q = city_name, appid = "{"My API"}", units="metric")
             # Make HTTP GET call for the given city
               response<-GET(forecast_url,query=forecast_query)
               # Note that the 5-day forecast JSON result is a list of lists. You can print the reponse to check the results
                 json_list<-content(response,as="parsed")
                 results <- json_list$list
                 
                   # Loop the json result
                   for(result in results) {
                       city <- c(city, city_name)
                       weather <- c(weather, json_result$weather[[1]]$main)
                       visibility <- c(visibility, json_result$visibility)
                       temp <- c(temp, json_result$main$temp)
                       temp_min <- c(temp_min, json_result$main$temp_min)
                       temp_max <- c(temp_max, json_result$main$temp_max)
                       pressure <- c(pressure, json_result$main$pressure)
                       humidity <- c(humidity, json_result$main$humidity)
                       wind_speed <- c(wind_speed, json_result$wind$speed)
                       wind_deg <- c(wind_deg, json_result$wind$deg)
                       forecast_datetime<-c(forecast_datetime,result$dt_txt)
                   }
    library(zoo)
    months <- as.numeric(format(as.Date(forecast_datetime),
                                '%m'))
    indx <- setNames( rep(c('winter', 'spring', 'summer',
                            'fall'),each=3), c(12,1:11))
    season <- unname(indx[as.character(months)])
    weather_df<-data.frame(city=city,weather=weather, 
                  visibility=visibility, 
                  temp=temp,
                  temp_min=temp_min, 
                  temp_max=temp_max, 
                  pressure=pressure, 
                  humidity=humidity, 
                  wind_speed=wind_speed, 
                  wind_deg=wind_deg,
                  forecast_datetime=forecast_datetime,
                  season=season)
                 # Add the R Lists into a data frame
                 }
     
       # Return a data frame
       return(df)
     }
cities <- c("Seoul", "Washington, D.C.", "Paris", "Suzhou")
cities_weather_df <- get_weather_forecaset_by_cities(cities)

And I replace my "MY API" with the API from openweathermap
The dataframe in the end has no data available despite the function and the code reading with no error.
How can I fix this?

Thanks in advance

CodePudding user response：

Your function returns df, instead of the data.frame you just made weather_df

If return(weather_df) doesnt work Id look into it line by line see if json_list/results are empty.