[英]"NoneType" error message for variables of class string type
我知道 re.search 返回一个匹配对象re.search(pattern, string, flags=0)我正在测试匹配是否成功,然后检索字符串。
# matchTest.py --- testing match object returns
import re
# expected_pattern = suburbRegex
suburbRegex = "(?s)(,_\S+\s)"
# line leading up to and including expected_pattern
mostOfLineRex = "(?s)(^.+,\S+)"
# expected_pattern to end of line
theRestRex = "(?s),_\S+\s\w+\s(.+)"
fileLines = ['173 ANDREWS John Frances 20 Bell_Road,_Sub_urbia Semi Retired\n']
for fileLine in fileLines:
result = re.search(suburbRegex, fileLine)
# print(type(result)) # re.Match
if(result):
patResult = re.search(suburbRegex, fileLine).group(0)
# print(patResult)
# print(type(patResult)) # str
# print(type(re.search(suburbRegex, fileLine).group(0))) # str
start = re.search(mostOfLineRex, fileLine)
if(start):
start = re.search(mostOfLineRex, fileLine).group(0)
# print(start)
print(type(start)) # str
end = re.search(theRestRex, fileLine)
if(end):
end = re.search(theRestRex, fileLine).group(0)
# print(end)
print(type(end)) # str
newFileLine = start + ' ' + end
else:
print("The listing does not have a suburb!")
# File "~\matchTest.py", line 31, in <module>
# newFileLine = start + ' ' + end
# TypeError: can only concatenate str (not "NoneType") to str
我检查过开始和结束的类型是<class 'str'>
那么为什么我会收到NoneType
错误?
您对re.search()
的返回值有错误的假设
>>> matches = re.search(r'[0-9]+', "testme 9"); matches; type(matches)
<re.Match object; span=(7, 8), match='9'>
<class 're.Match'>
>>> matches = re.search(r'[0-9]+', "testme"); matches; type(matches)
<class 'NoneType'>
这解释了您在尝试连接start
" "
和end
时的错误。
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