Python file operation exercises

1. Read a file and display all lines except the lines starting with #.

f=open('2017级-学生信息-1.txt','r')
while 1:
    content=f.readlines()
    for i in content:
        if (i[0] == '#'):
            continue
        else:
            print(i)
    break
f.close()

Operation result:


2. It is known that there are some numbers stored in the text file. Please write a program to read all the numbers and output them after sorting.

f=open('number.txt','r')
total=f.read()
print(total)
number=[]
for i in total:
    number.append(i)
number.sort()
print(number)
f.close()

Problems encountered: how to recognize numbers other than 10, and how to delete if there are spaces and line breaks in the text.
Operation result:

3. Open an English text file, encrypt each letter in the file and write it to a new file. The encryption method is: change A into B, B into C,… Y becomes Z , Z becomes A; a becomes b, b becomes ... z becomes a, other characters do not change.

f=open('English.txt','r')
content = f.read()
newStr = ""
for string in content:
    temp = ord(string)#ord返回对应的ASCII值
    if temp in range(65,91):
        if temp == 90:
            char1 = chr(temp-25)#chr当前整数对应的ASCII字符
            newStr += char1
        else:
            char2 = chr(temp+1)
            newStr += char2
    elif temp in range(97,123):
        if temp == 122:
            char3 = chr(temp-25)
            newStr += char3
        else:
            char4 = chr(temp + 1)
            newStr += char4
    else:
        newStr = newStr+string
f.close()
f2 = open("English加密后.txt","w")
f2.write(newStr)
f2.close()

Operation result:

4. Open an English text file, and change the uppercase letters to lowercase and lowercase letters to uppercase.

f=open('English.txt','r')
content=f.read()
content=content.swapcase()#swapcase() 方法用于对字符串的大小写字母进行转换
print(content)
f=open('English.txt','w')
f.write(content)
f.close()

Operation result:

5. In daily life, we often meet certain needs to modify the file name. With the help of the file operation we just learned, write a small program that can modify the file name in batches

import os
files=os.listdir("./")
#print(files)
i=0
for file in files:
    fileFormat=files[i][files[i].find("."):]
    #print(fileFormat)

    fileName=files[i][:files[i].find(".")]
    fileName.strip()
    #print(fileName)
    if(fileFormat.strip() == ".txt".strip()):
        os.rename(fileName+fileFormat,"2017-学生信息-"+str(i+1)+fileFormat)
    i=i+1