python - 正则表达式在熊猫中拆分
问题描述
你好,我有一个df,比如
COL1
NW_011625257.1_0
NW_011623521.1_1
NW_011623521.3_1
NW_011623521.4_1
NW_011623521.1
JZSA01007324.1_2
scaffold_1463_2
scaffold_1463
我想减到最后'_'
并得到
COL1 COL2
NW_011625257.1 0
NW_011623521.1 1
NW_011623521.3 1
NW_011623521.4 1
NW_011623521.1 NaN
JZSA01007324.1 2
scaffold_1463 2
scaffold_1463 NaN
到目前为止,我尝试过:
df[['COL1','COL2']] = df.COL1.str.split(r'_(?!.*_)', expand=True)
相反,我得到了这种输出:
COL1 COL2
NW_011625257.1 0
NW_011623521.1 1
NW_011623521.3 1
NW_011623521.4 1
NW 011623521.1
JZSA01007324.1 2
scaffold_1463 2
scaffold 1463
这是我要选择的示例
解决方案
您可以使用
df[['COL1','COL2']] = df.COL1.str.split(r"(?<=\d)_(?=\d+$)", expand=True)
查看正则表达式演示
图案细节:
(?<=\d)
- 当前位置之前必须有一个数字_
- 一个下划线(?=\d+$)
- 当前位置的右侧必须有 1 个以上的数字和字符串的结尾。
熊猫测试:
df = pd.DataFrame({'COL1': ['NW_011625257.1_0','NW_011623521.1_1','NW_011623521.3_1','NW_011623521.4_1','NW_011623521.1','JZSA01007324.1_2','scaffold_1463_2','scaffold_1463']})
>>> df[['COL2','COL3']] = df.COL1.str.split(r"(?<=\d)_(?=\d+$)", expand=True)
>>> df
COL1 COL2 COL3
0 NW_011625257.1_0 NW_011625257.1 0
1 NW_011623521.1_1 NW_011623521.1 1
2 NW_011623521.3_1 NW_011623521.3 1
3 NW_011623521.4_1 NW_011623521.4 1
4 NW_011623521.1 NW_011623521.1 None
5 JZSA01007324.1_2 JZSA01007324.1 2
6 scaffold_1463_2 scaffold_1463 2
7 scaffold_1463 scaffold_1463 None