使用函数“group_by”的for不起作用(R)

library(dplyr)

# 示例数据框
df <- data.frame(
  group = c("A", "B", "A", "B"),
  value = c(1, 2, 3, 4)
)

# 分组操作
grouped_df <- df %>% group_by(group)

# 错误的 for 循环示例
for (i in 1:nrow(df)) {
  grouped_df <- df %>% group_by(group)
  print(grouped_df)
}

# 正确的做法
result <- df %>% group_by(group) %>% summarise(mean_value = mean(value))
print(result)

# 示例：计算每个组的总和
summed_df <- df %>% group_by(group) %>% summarise(total_value = sum(value))
print(summed_df)

library(dplyr)

# 示例数据框
df <- data.frame(
  group = c("A", "B", "A", "B"),
  value = c(1, 2, 3, 4)
)

# 分组并计算平均值
result <- df %>% group_by(group) %>% summarise(mean_value = mean(value))
print(result)