将R中相同日期的不同行的数据相加

# 创建示例数据框
df <- data.frame(
  date = c("2023-01-01", "2023-01-01", "2023-01-02", "2023-01-02"),
  value = c(10, 20, 30, 40)
)

# 安装并加载dplyr包
install.packages("dplyr")
library(dplyr)

# 按日期分组并求和
result <- df %>%
  group_by(date) %>%
  summarize(total_value = sum(value))

# 查看结果
print(result)

# 安装并加载lubridate包
install.packages("lubridate")
library(lubridate)

# 将日期列转换为统一的日期格式
df$date <- ymd(df$date)

# 再次按日期分组并求和
result <- df %>%
  group_by(date) %>%
  summarize(total_value = sum(value))

# 查看结果
print(result)

# 处理空值
df <- df %>%
  mutate(value = ifelse(is.na(value), 0, value))

# 再次按日期分组并求和
result <- df %>%
  group_by(date) %>%
  summarize(total_value = sum(value))

# 查看结果
print(result)