python过滤文件内容

Question

我是 python 新手，我正在尝试执行以下任务，但我的输出与预期的不同。任何人都可以帮我解决这里的问题吗？感谢您的帮助！

作业：

在第三个程序中，我们来看看文件内容的分类。在与源代码相同的目录中是一个文件“strings.txt”，其中包含多行随机字符串。这些行可以分为两组：只有字母（a-z、A-Z）和数字（0-9）的行，以及也有随机特殊字符（?、&、@、$ ...）的行。

创建一个程序，从文件中读取所有行并测试这些行。如果该行只有字母和/或数字，程序将打印“[line] was ok.”。如果该行有特殊字符，程序应该打印“[line] was invalid.”。当程序运行时，它会打印出如下内容：

5345m345ö34l was ok.
no2no123non4 was ok.
noq234n5ioqw#% was invalid.
%#""SGMSGSER was invalid.
doghdp5234 was ok.
sg,dermoepm was invalid.
43453-frgsd was invalid.
hsth())) was invalid.
bmepm35wae was ok.
vmopaem2234+0+ was invalid.
gsdm12313 was ok.
bbrbwb55be3"?"#? was invalid.
"?"#%#"!%#"&"?%%"?#?#"?" was invalid.
retrte#%#?% was invalid.
abcdefghijklmnopqrstuvxy was ok.

建议一次读取一行，使用 isalmun() 字符串测试对其进行测试，然后从那里继续。还要记住，字符串也可能以换行符 (\n) 结尾，这是允许的，但如果没有被切掉，则 .isalnum() 测试失败。 示例输出

5345m34534l was invalid.
no2no123non4 was ok.
noq234n5ioqw#% was invalid.
%#""SGMSGSER was invalid.
doghdp5234 was ok.
sg,dermoepm was invalid.
43453-frgsd was invalid.
hsth())) was invalid.
bmepm35wae was ok.
vmopaem2234+0+ was invalid.
gsdm12313 was ok.
gswrgsrdgrsgsig45 was ok.
)/(/)(#=%#)%/ was invalid.
++-+-+--+--+-+>-<+-<<_<-+>>++ was invalid.

我的代码是

handle = open("strings.txt","r")
content = handle.read()
content.isalnum()
for i in content:
    if content.isalnum()==True:
        print(content,"was ok")
    else:
        print(content,"was invalid")

handle.close()

我的输出是

5345m34534l
no2no123non4
noq234n5ioqw#%
%#""SGMSGSER
doghdp5234
sg,dermoepm
43453-frgsd
hsth()))
bmepm35wae
vmopaem2234+0+
gsdm12313
gswrgsrdgrsgsig45
)/(/)(#=%#)%/
++-+-+--+--+-+>-<+-<<_<-+>>++. was invalid
5345m34534l
no2no123non4
noq234n5ioqw#%
%#""SGMSGSER
doghdp5234
sg,dermoepm
43453-frgsd
hsth()))
bmepm35wae
vmopaem2234+0+
gsdm12313
gswrgsrdgrsgsig45
)/(/)(#=%#)%/
++-+-+--+--+-+>-<+-<<_<-+>>++. was invalid
5345m34534l
no2no123non4
noq234n5ioqw#%
%#""SGMSGSER
doghdp5234
sg,dermoepm
43453-frgsd
hsth()))
bmepm35wae
vmopaem2234+0+
gsdm12313
gswrgsrdgrsgsig45
)/(/)(#=%#)%/
++-+-+--+--+-+>-<+-<<_<-+>>++. was invalid

# etc ad nauseum...

我做错了什么？

Answer 1

handle = open("strings.txt","r")
content = handle.read()  # <= here you read in the entire file
content.isalnum()
for i in content:      # <= here you iterate over each **character** of the file
    if content.isalnum()==True:
        print(content,"was ok")
               # ^ here you print the entire input file each time
    else:
        print(content,"was invalid")
               # ^ (ditto) which is why you have so much output
handle.close()

不如试试

with open("strings.txt") as inf:
    for line in inf:
        line = line.rstrip()
        if line.isalnum():
            print("{} was ok".format(line))
        else:
            print("{} was invalid".format(line))

Answer 2

我认为输出是错误的，因为您将整个文件读入一个字符串并且 循环遍历文件的所有字符。您的“内容”变量是一个字符串，因此代码不会逐行检查。它检查整个文件并打印出整个文件无效。

我的回答：

file = open("strings.txt","r") content = file.readlines() for i in content: if i.rstrip().isalnum(): print(i+" was ok.") else: print(i+" was invalid.") file.close()

Answer 3

这是我的作业代码，它提供了所需的输出：

filename="strings.txt"
handle = open("strings.txt","r") #read file
text = handle.readlines() # read lines by lines
for i in text:
    if i.rstrip().isalnum():
        print(i.rstrip()," was ok.")
    else:
        print(i.rstrip()," was invalid.")
handle.close()

Answer 4

handle = open("strings.txt","r")

line = ""
while True:
    line = handle.readline()
    if line == "":
        break
    line = line[:-1]
    if line.isalnum() == False:
        print(line,"was invalid.")
    else:
        print(line,"was ok.")

handle.close()

Answer 5

file = open("strings.txt", "r")
    content = file.readlines()
    file.close()
    for line in content:
        line = line.strip()
        if line.isalnum():
            print(line + " was ok.")
        else:
            print(line + " was invalid.")