R-在if循环中比较hhmm格式数据

发布于 2025-01-14 08:40:24 字数 749 浏览 10 评论 0原文

我有一个名为 df 的数据框，如下所示。

我想添加第三列，类型，遵循以下规则：

  for (k in 1 : nrow(df)){
    if(df$HHmm >= 0860 & df$HHmm <= 1060){
      df[k, 'type'] = "r1"
    }else{
      df[k, 'type'] = "c"
    }
  }

但我收到警告：

In if (df$HHmm >= 0860 & df$HHmm <= 1060) { ... :
  the condition has length > 1 and only the first element will be used

并且我得到了不良结果，如下所示。

ID HHmm type
1  0840 r1
2  0910 r1
3  1050 r1
4  1210 r1
5  1230 r1

理想的结果应该如下所示

ID HHmm type
1  0840 c
2  0910 r1
3  1050 r1
4  1210 c
5  1230 c

有人能发现这里出了什么问题吗？如何在if循环中比较HHmm时间格式数据？

原文

I have a dataframe named df, just as below.

I want to add a third column, type, that follows these rules:

  for (k in 1 : nrow(df)){
    if(df$HHmm >= 0860 & df$HHmm <= 1060){
      df[k, 'type'] = "r1"
    }else{
      df[k, 'type'] = "c"
    }
  }

but I get the warning:

In if (df$HHmm >= 0860 & df$HHmm <= 1060) { ... :
  the condition has length > 1 and only the first element will be used

and I got a undesirable results, just like below.

ID HHmm type
1  0840 r1
2  0910 r1
3  1050 r1
4  1210 r1
5  1230 r1

The desirable resultes should be like below

ID HHmm type
1  0840 c
2  0910 r1
3  1050 r1
4  1210 c
5  1230 c

Can anyone spot what's wrong here? How to compare HHmm time format data in if loop?

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做个少女永远怀春 2025-01-21 08:40:24

您需要定义索引k；例如df$HHmm[k]。

  for (k in 1:nrow(df)){
    if(df$HHmm[k] >= 0860 & df$HHmm[k] <= 1060){
      df[k, 'type'] = "r1"
    }else{
      df[k, 'type'] = "c"
    }
  }

You need to define the index k; e.g. df$HHmm[k].

  for (k in 1:nrow(df)){
    if(df$HHmm[k] >= 0860 & df$HHmm[k] <= 1060){
      df[k, 'type'] = "r1"
    }else{
      df[k, 'type'] = "c"
    }
  }

回复收藏 0 原文

偷得浮生 2025-01-21 08:40:24

您不需要（也不应该）使用循环在 R 中执行此类操作。它更慢、更冗长且更难以理解。

您只想创建一个名为 type 且值为“c”的列，然后将值“r1”分配给满足条件的列的子集：

df$type  <- "c"
df$type[df$HHmm >= 0860 & df$HHmm <= 1060]  <- "r1"
df

# Output
#   ID HHmm type
# 1  1  840    c
# 2  2  910   r1
# 3  3 1050   r1
# 4  4 1210    c
# 5  5 1230    c

You do not need to (and should not) use a loop to do this kind of operation in R. It is slower, more verbose and harder to comprehend.

You just want to create a column called type with the value "c" and then assign the value "r1" to the subset of the column that meets your condition:

df$type  <- "c"
df$type[df$HHmm >= 0860 & df$HHmm <= 1060]  <- "r1"
df

# Output
#   ID HHmm type
# 1  1  840    c
# 2  2  910   r1
# 3  3 1050   r1
# 4  4 1210    c
# 5  5 1230    c

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