以逗号分隔字符串,但忽略双引号内的逗号
现有数据格式如下,需要以逗号分隔字符串,但忽略双引号内的逗号,即
"Anemia, Hemolytic"
内的逗号不进行分割
a = '11-BETA-HSD3,100174880,"Anemia, Hemolytic",MESH:D000743,,"Water Pollutants, Chemical",4.49,,22425172'
需要的效果如下:
['11-BETA-HSD3', '100174880', '"Anemia, Hemolytic"', 'MESH:D000743', '', '"Water Pollutants, Chemical"', '4.49', '', '22425172']
目前想到两种方法,如下:
使用正则re.split进行字符串分割
使用csv模块的reader进行分割
使用正则re.split进行字符串分割
import re
a = '11-BETA-HSD3,100174880,"Anemia, Hemolytic",MESH:D000743,,"Water Pollutants, Chemical",4.49,,22425172'
b = re.split(r',\s*(?![^"]*\"\,)', a)
print(len(b))
print(b)
['11-BETA-HSD3', '100174880', '"Anemia, Hemolytic"', 'MESH:D000743', '', '"Water Pollutants, Chemical"', '4.49', '', '22425172']
r',\s*(?![^"]*\"\,)'
r
表示原始字符串,,
表示以,分割
\s
表示匹配空白字符,*
表示匹配前一个字符0次或者无数次,\s*
即表示如果是,,
会匹配为''
,这样数据分割出来的列表长度一致,下标对应的字符串不会混乱
(?![^"]*\"\,)
表示匹配后面有"asg",
的逗号,但是不匹配后面是asg",
的逗号,重点是这个,分为两部分解释
[^"]*\"\,
在原始字符串模式下,表示匹配asdgdg",
但是不匹配"asdgdg",
1(?!2)
表示匹配13
中的1,但是不匹配12
中的1
Positive and Negative Lookahead
(pattern),(?:pattern),(?=pattern),(?!pattern)
import re
a = '11-BETA-HSD3,100174880,"Anemia, Hemolytic",MESH:D000743,,"Water Pollutants, Chemical",4.49,,"22425172,test"'
b = re.split(r',\s*(?![^"]*\"\,)', a)
print(len(b))
print(b)
['11-BETA-HSD3', '100174880', '"Anemia, Hemolytic"', 'MESH:D000743', '', '"Water Pollutants, Chemical"', '4.49', '', '"22425172', 'test"']
目前的解决办法是,在字符串后面加上,
就可以让字符串尾部双引号内的逗号不被分割,但是这样分割出来的列表长度+1,列表最后一个元素为''
import re
a = '11-BETA-HSD3,100174880,"Anemia, Hemolytic",MESH:D000743,,"Water Pollutants, Chemical",4.49,,"22425172,test"'
a = a + ','
b = re.split(r',\s*(?![^"]*\"\,)', a)
print(len(b))
print(b)
['11-BETA-HSD3', '100174880', '"Anemia, Hemolytic"', 'MESH:D000743', '', '"Water Pollutants, Chemical"', '4.49', '', '"22425172,test"', '']
使用csv模块的reader进行分割
import csv
a = '11-BETA-HSD3,100174880,"Anemia, Hemolytic",MESH:D000743,,"Water Pollutants, Chemical",4.49,,22425172'
b = [a]
reader = csv.reader(b, delimiter=',')
for row in reader:
print(len(row))
print(row)