R语言：从数据文件中提取小麦生长指标并计算统计量

# 读取数据文件\n\n\n\n\n\ndf \u003c- fread("E:/trainingdata/wheatOUTfile/75csv/Hebei_bazhou.csv")\n\n# 提取起始年份和结束年份\n\n\n\n\n\nstart_year \u003c- 1981\n\nend_year \u003c- 2019\n\n# 创建一个空的结果数据框\n\n\n\n\n\nresult \u003c- data.frame(Year = integer(), Avg_Temperature = numeric(), Total_Rainfall = numeric(), gdd = numeric(), yield_at_maturity = numeric())\n\n# 循环计算1981-2019年的结果\n\n\n\n\n\nfor (year in start_year:end_year) {\n\t# 提取播种日期(day1) 和成熟日期(day2)\n\tday1 \u003c- df \u003e%\n\t\tfilter(year == year, StageName == "sowing") \u003e%\n\t\tselect(simulation_days)\n\n\tday2 \u003c- df \u003e%\n\t\tfilter(year == year+1, StageName == "maturity") \u003e%\n\t\tselect(simulation_days)\n\n\t# 计算平均温度\n\tav_temperature \u003c- df \u003e%\n\t\tfilter(simulation_days \u003e= day1[[1]] & simulation_days \u003c= day2[[1]]) \u003e%\n\t\tsummarize(Avg_Temperature = mean(MaxT, na.rm = TRUE))\n\n\t# 计算总降雨量\n\ntotal_rainfall \u003c- df \u003e%\n\t\tfilter(simulation_days \u003e= day1[[1]] & simulation_days \u003c= day2[[1]]) \u003e%\n\t\tsummarize(Total_Rainfall = sum(Rain, na.rm = TRUE))\n\n\t# 计算gdd\n\tgdd \u003c- df \u003e%\n\t\tfilter(simulation_days \u003e= day1[[1]] & simulation_days \u003c= day2[[1]]) \u003e%\n\t\tsummarize(gdd = sum((MaxT+MinT)/2, na.rm = TRUE))\n\n\t# 提取成熟时的产量\n\tyield_at_maturity \u003c- df \u003e%\n\t\tfilter(year == year+1, StageName == "maturity") \u003e%\n\t\tselect(yield)\n\n\t# 将结果添加到结果数据框中\n\tresults \u003c- rbind(result, data.frame(Year = year, Avg_Temperature = avg_temperature$Avg_Temperature, Total_Rainfall = total_rainfall$Total_Rainfall, gdd = gdd$gdd, yield_at_maturity = yield_at_maturity$yield))\n}