如何将具有不同日期的Series组合到一个DataFrame中

Question

我从quandl和fred中获取了一些数据，然后尝试将它们放入相同的CSV文件中。但是我的$project数据在csv文件中丢失。
这是我的代码：

df <- data.frame(column_1 = c("A", "B", "C"), column_2 = c("w,x", "z", "q,r,s"))
l_vals <- strsplit(as.character(df$column_2), split = ",", perl =TRUE)
l_append = list()
for(i in seq_along(l_vals)){
  l_append <- c(l_append,paste0(df$column_1[i], l_vals[[i]]))
}

unlist(l_append)

Answer 1

fredapi.get_series的规范定义了必需的参数（当指定了observation_start时）：

 Parameters
        ----------
        series_id : str
            Fred series id such as 'CPIAUCSL'
        observation_start : datetime or datetime-like str such as '7/1/2014', optional
            earliest observation date
        observation_end : datetime or datetime-like str such as '7/1/2014', optional
            latest observation date
        kwargs : additional parameters
            Any additional parameters supported by FRED. You can see https://api.stlouisfed.org/docs/fred/series_observations.html for the full list

在我看来，您的日期格式不正确-尝试使用

spot_price = fred.get_series('DCOILBRENTEU',observation_start='1/1/2017')

相反。