AttributeError: 'NoneType' 对象没有属性 'lower' python
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/19537520/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
AttributeError: 'NoneType' object has no attribute 'lower' python
提问by john john
My abc.txtfile looks like this
我的 abc.txtfile 看起来像这样
Mary Kom 28 F
Emon Chatterje 32 M
Sunil Singh 35 M
Now i am getting the desired result with the following traceback:Please help me out. I am not getting where am i going wrong
现在我通过以下回溯得到了想要的结果：请帮帮我。我不明白我哪里出错了
Enter for Search Criteria
1.FirstName 2.LastName 3.Age 4.Gender 5.Exit 1
Enter FirstName :m
Mary Kom 28 F
Emon Chatterje 32 M
Traceback (most recent call last):
File "testcode.py", line 50, in <module>
if (records.searchFName(StringSearch)):
File "testcode.py", line 12, in searchFName
return matchString.lower() in self.fname.lower()
AttributeError: 'NoneType' object has no attribute 'lower'
My Code:
我的代码：
#!usr/bin/python
import sys
class Person:
def __init__(self, firstname=None, lastname=None, age=None, gender=None):
self.fname = firstname
self.lname = lastname
self.age = age
self.gender = gender
def searchFName(self, matchString):
return matchString.lower() in self.fname.lower()
def searchLName(self, matchString):
return matchString.lower() in self.lname.lower()
def searchAge(self, matchString):
return str(matchString) in self.age
def searchGender(self, matchString):
return matchString.lower() in self.gender.lower()
def display(self):
print self.fname, self.lname, self.age, self.gender
f= open("abc","r")
list_of_records = [Person(*line.split()) for line in f]
f.close()
found = False
n=0
n1 = raw_input("Enter for Search Criteria\n1.FirstName 2.LastName 3.Age 4.Gender 5.Exit " )
if n1.isdigit():
n = int(n1)
else:
print "Enter Integer from given"
sys.exit(1)
if n == 0 or n>5:
print "Enter valid search "
if n == 1:
StringSearch = raw_input("Enter FirstName :")
for records in list_of_records:
if (records.searchFName(StringSearch)):
found = True
records.display()
if not found:
print "No matched record"
if n == 2:
StringSearch = raw_input("Enter LastName :")
for records in list_of_records:
if records.searchLName(StringSearch):
found = True
records.display()
if not found:
print "No matched record"
if n == 3:
StringSearch = raw_input("Enter Age :")
if (StringSearch.isdigit()):
StringSearch1 = int(StringSearch)
else:
print "Enter Integer"
sys.exit()
for records in list_of_records:
if records.searchAge(StringSearch):
found = True
records.display()
if not found:
print "No matched record"
if n == 4:
StringSearch = raw_input("Enter Gender(M/F) :")
for records in list_of_records:
if records.searchGender(StringSearch):
found = True
records.display()
if not found:
print "No matched record"
if n == 5:
sys.exit(1)
Please help solve my problrm to where am i going wrong ??
请帮助解决我的问题，我哪里出错了？？
采纳答案by Martijn Pieters
You have a Person()class with no firstname. You created it from an empty line in your file:
你有一个Person()没有firstname. 您从文件中的空行创建它：
list_of_records = [Person(*line.split()) for line in f]
An empty line results in an empty list:
空行导致空列表：
>>> '\n'.split()
[]
which leads to Person(*[])being called, so a Person()instance was created with no arguments, leaving the default firstname=None.
这导致Person(*[])被调用，因此Person()创建了一个没有参数的实例，保留默认firstname=None.
Skip empty lines:
跳过空行：
list_of_records = [Person(*line.split()) for line in f if line.strip()]
You may also want to default to empty strings, or specifically test for Nonevalues before treating attributes as strings:
您可能还希望默认为空字符串，或者None在将属性视为字符串之前专门测试值：
def searchFName(self, matchString):
return bool(self.fname) and matchString.lower() in self.fname.lower()
Here bool(self.fname)returns Falsefor empty or Nonevalues, giving you a quick Falsereturn value when there is no first name to match against:
这里bool(self.fname)返回False空或None值，False当没有名字匹配时为您提供快速返回值：
>>> p = Person()
>>> p.fname is None
True
>>> p.searchFName('foo')
False
