Python 将dataframe列中的某些多个值重命名为另一个单个值

我有一个数据帧，大小为1GB，下面是一个虚拟帧

df <- data.frame(group=rep(c("A", "B", "C","D","E","F","G","H"), each=4),height=sample(100:150, 16))
df
   group height
1      A    105
2      A    119
3      B    108
4      B    114
5      C    109
6      C    111
7      D    148
8      D    121
9      E    133
10     E    101
11     F    143
12     F    135
13     G    147
14     G    141
15     H    150
16     H    145

任何关于R或熊猫的建议都非常好。

---

谢谢您

带和布尔掩码的熊猫/Numpy解决方案：

print (df['group'] =='B')
1     False
2     False
3     False
4     False
5      True
6      True
7      True
8      True
9     False
10    False
11    False
12    False
Name: group, dtype: bool

df['group'] = np.where(df['group'] == 'B','NC','PC')
print (df)

   group  height
1     PC     113
2     PC     118
3     PC     128
4     PC     143
5     NC     109
6     NC     141
7     NC     142
8     NC     129
9     PC     127
10    PC     102
11    PC     108
12    PC     107

具有双

np的解决方案。其中

：

df['group'] = np.where(df['group'].isin(['B','G','H']), 'NC',
              np.where(df['group'] == 'A', 'PC', 'NON'))

print (df)
   group  height
1     PC     105
2     PC     119
3     NC     108
4     NC     114
5    NON     109
6    NON     111
7    NON     148
8    NON     121
9    NON     133
10   NON     101
11   NON     143
12   NON     135
13    NC     147
14    NC     141
15    NC     150
16    NC     145

在R中，您可以尝试：

首先转换为字符，然后直接替换值

df$group <- as.character(df$group); 
df$group[df$group %in% c("B")] <- "NC"

---

您还可以替换组名，如下所示

    df$group=as.character(df$group)
    df$group[c(3:4,13:16)]='NC'
    df$group[c(1:2)]='PC'
    df$group[c(5:12)]='NON'

---

事实上，我的数据框相当大，它的值比A、B和C都多。我可以编辑我的问题。对不起，请你看看我的问题。我现在已经编辑了。是的，

NON

的意思是

NaN

不是一个数字？不是NaN..它是一个字符串

df['group'] = np.where(df['group'].isin(['B','G','H']), 'NC',
              np.where(df['group'] == 'A', 'PC', 'NON'))

print (df)
   group  height
1     PC     105
2     PC     119
3     NC     108
4     NC     114
5    NON     109
6    NON     111
7    NON     148
8    NON     121
9    NON     133
10   NON     101
11   NON     143
12   NON     135
13    NC     147
14    NC     141
15    NC     150
16    NC     145

df$group <- as.character(df$group); 
df$group[df$group %in% c("B")] <- "NC"

df$group2 <- ifelse( df$group %in% c("B", "H", "G"), "NC", ifelse(df$group %in% c("A"), "PC", "NON"))
head(df, 10)
   group height group2
1      A    139     PC
2      A    114     PC
3      A    132     PC
4      A    141     PC
5      B    107     NC
6      B    101     NC
7      B    122     NC
8      B    129     NC
9      C    100    NON
10     C    108    NON

    df$group=as.character(df$group)
    df$group[c(3:4,13:16)]='NC'
    df$group[c(1:2)]='PC'
    df$group[c(5:12)]='NON'