python第十章 文件與異常

#練習題網站：https://www.xz577.com/j/129.html
#文件與異常
#同名文件下可打開
with open('pi.txt') as file_object:
    contents=file_object.read()
    print(contents)
    print(contents.rstrip())
    #read()函數會默認返回空行，所以可以用rstrip()刪除
    
#打開同目錄下的文件夾中包含的文件
with open('practice\pi.txt') as file_object: #windows使用反斜槓'\'，當然正斜槓也可以
    contents=file_object.read()
    print(contents)
   
#打開任意處的文件：精確查找
with open('C:\CODING\.idea\practice\pi.txt') as file_object:
    #上面的r是爲了保證萬無一失 因爲反斜在python裏面爲轉義字符
    #讀取整個文件進行打印
    contents=file_object.read()
    print(contents.rstrip())
    
#逐行讀取 遍歷整個文件
source='C:\CODING\.idea\practice\pi.txt'

with open(source) as file_object:
    for line in file_object:
        print(line.rstrip()) #因爲默認會多空行所以用rtrip
        
 #使用with時，open返回的對象只在with代碼塊中使用
#如果想要在with之外使用，那麼先將文件的各行儲存在列表中
source='C:\CODING\.idea\practice\pi.txt'

with open(source) as file_object:
    lines=file_object.readlines()
    #readlines讀取每行並存儲在列表中
    #注意不是readline！！！

for line in lines:
    print(line.rstrip())
    
#使用文件內的內容 此處是把pi存儲在字符串內
pi_string=''
for line in lines:
    pi_string+=line.strip()

print(pi_string)
print(len(pi_string))
                                                                                                              
#如果想把字符串轉化爲數值 可以使用int或者float
a=float(pi_string)
print(a)

#10.2練習題
source='C:\CODING\.idea\practice\pi.txt'
#將python替換爲c
with open(source) as file_object:
    lines=file_object.readlines()
for line in lines:
    print(line.replace('python','c').rstrip())
    
#寫入文件
#w爲寫入模式，r爲讀取模式，a爲附加模式，r+爲讀取和寫入
#注意當文件不存在時，將自動創建，但是當文件
#但是當文件不存在的時候將自動創建文件
#如果文件存在使用了w那麼原來的內容將被清除
file_name='p.txt'
with open(file_name,'w') as file_object:
    file_object.write("I love python!!!\nAnd I am so crazy about programmming!!!")
#下面是三種方法：
with open(file_name) as file_object:
    content = file_object.read()
    print(content)
    for line in file_object:
        print(line.rstrip())
    lines = file_object.readlines()
for line in lines:
    print(line.rstrip())    

#寫入多行
file_name='p.txt'
with open(file_name,'w') as file_object:
    file_object.write("hello world!\n") #注意此處如果不加\n那麼兩行就會變成一行
    file_object.write("I love python!")
with open(file_name) as file_object:
    for line in file_object:
        print(line.rstrip())
#附加模式寫入多行
with open(file_name,'a') as file_object:
    file_object.write("\nlets do this\n")
    #注意此處前面需要一個\n 否則會和成一行
    file_object.write("I love python!")
with open(file_name) as file_object:
    for line in file_object:
        print(line.rstrip())

#10.3練習 輸入訪客名稱
file_name='hello.txt'
with open(file_name,'w') as file_object:
    a=input("Your name:")
    file_object.write(a)
with open(file_name) as file_object:
    con=file_object.read()
    print(con.rstrip())
    
#10.4練習 多次輸入名字 每個名字一行
file_name='hello.txt'
with open(file_name,'w') as file_object:
    active=True
    while active:
        a=input("Enter your name:")
        print("Hello!"+a)
        file_object.write(a+'\n')
        b=input("Do you want to go on? YES PR NO")
        if b!='YES':
            active=False
with open(file_name) as file_object:
    con=file_object.read()
    print(con.rstrip())
    
#使用try-except代碼塊
try:
    print(5/0)
except ZeroDivisionError:
    print("You cannot divide by Zero!")
#使用代碼塊避免崩潰
while True:
    f_n=input("First number:")
    if f_n=='q':
        break
    s_n=input("Second number:")
    if s_n=='q':
        break
    try:
        answer=int(f_n)/int(s_n)
        print(answer)
    except ZeroDivisionError:
        print("You cannot do this!")
#當然也可以使用else
try:
        answer=int(f_n)/int(s_n)
except ZeroDivisionError:
        print("You cannot do this!")
else:
    print(answer)
   
#處理FileNotFoundError
file_name="pppp.txt"
try:
    with open(file_name) as file_o:
        con=file_o.read()
        print(con.rstrip())
except FileNotFoundError:
    print(file_name+".txt does not exist!")
    
#分析文本
file_name="hello.txt"
try:
    with open(file_name) as f_o:
        con=f_o.read()
except FileNotFoundError:
    print("Sorry! The file cnnot be found!")
else:
    words=con.split()
    #split將字符串按照空格/行 切成列表
    s=len(words)
    print("The file "+file_name+".txt has about "+str(s)+" words.")              
        
#爲了方面使用 可以設置函數
def count(file_name):
    try:
        with open(file_name) as f_o:
            con = f_o.read()
    except FileNotFoundError:
        print("Sorry! The file cnnot be found!")
    else:
        words = con.split()
        # split將字符串按照空格/行 切成列表
        s = len(words)
        print("The file " + file_name + ".txt has about " + str(s) + " words.")

file_name="hello.txt"
count(file_name)

#加循環
file_collection=['hello.txt','pp.txt','hahah.txt']
for file_name in file_collection:
    count(file_name)            

#自主選擇報告哪些程序錯誤
try:
    --snip--
except:
     pass
else:
    --snip--
    
#10.6+10.7 練習 加法運算 實現多次輸入 錯誤提示
def adddd(a,b):
    try:
        a=int(a)
        b=int(b)
    except ValueError:
        print("Please enter numbers instead of text.")
    else:
        print(a+b)
while True:
    a=input("Enter the first number:")
    b=input("Enter the second number:")
    adddd(a,b)
    c=input("Go on or not?YES OR NO")
    if c!="YES":
        break    

#10.8練習 讀取文件 異常
file_name=['cats.txt','dogs.txt','hh.txt']
with open(file_name[0],'w') as file_o:
    file_o.write("mory\njojo\nhapo")
with open(file_name[1],'w') as file_o:
    file_o.write("mmory\njkkojo\nhhhhapo")
def read_name(a):
    try:
        with open(i) as ob:
            con=ob.read()
            print(con.rstrip())
    except FileNotFoundError:
        print("The file "+i+" cannot be found.")
for i in file_name:
    read_name(i)
    
#存儲數據
#使用json模塊來進行存儲：將數據存儲在文件對象中，格式是列表
import json
numbers=[2,3,4,5]
file_name='numbersjson.txt'
with open(file_name,'w') as ob:#藉助ob對象最終把數據存儲在number.json裏面
    json.dump(numbers,ob)
#用load函數來讀出
with open(file_name) as ob:
    number=json.load(ob)
print(number)    

#保存和讀取用戶輸入數據+重構
import json
def get_user():
    file_name='usernamer.txt'
    try:
        with open(file_name) as file_ob:
            username=json.load(file_ob)
    except FileNotFoundError:
        username=input("What's your name?")
        with open(file_name,'w') as file_ob:
            json.dump(username,file_ob)
        print("We will remember when you are back,"+username+"!")
    else:
        print("Welcome back!"+username)

get_user()
#進而在另一個.py模塊中
import ha
ha.get_user()

#函數進一步的重構
import json
def get_user_stored():
    file_name='userna.txt'
    try:
        with open(file_name) as file_ob:
            username=json.load(file_ob)
    except FileNotFoundError:
        return None
    else:
        return username

def greet_use():
    username=get_user_stored()
    if username:
        print("Welcome back!" + username)
    else:
        username=input("What's your name?")
        file_name = 'userna.txt'
        with open(file_name,'w') as file_ob:
            json.dump(username,file_ob)
        print("We will remember when you are back,"+username+"!")
greet_use()

#函數進進一步的重構
import json
def get_user_stored():
    file_name='userna.txt'
    try:
        with open(file_name) as file_ob:
            username=json.load(file_ob)
    except FileNotFoundError:
        return None
    else:
        return username

def get_new_name():#函數定義時的括號以及冒號！！！
    username = input("What's your name?")
    file_name = 'userna.txt'
    with open(file_name, 'w') as file_ob:
        json.dump(username, file_ob)
    return username

def greet_use():
    username=get_user_stored()
    if username:
        print("Welcome back!" + username)
    else:
        username=get_new_name()
        print("We will remember when you are back,"+username+"!")

greet_use()
#重構是爲了目的性更強

#10.12 功能：
#記錄用戶輸入數字；
#存儲自定義文件內；
#如果不輸入數字提示並且可以重新輸入
#可以多次循環輸入
#紀念一下這個實現完整功能的程序！！奧利給！！
import json

def num_stored():
    try:
        f_n=input("What's your favorite number?\n")
        with open(file_name,'w') as ob:
            json.dump(f_n,ob)
        f_n = int(f_n)
    except ValueError:
        print("Enter number please~")
        return 0
def read_num(file_name):
    with open(file_name) as ob:
        con=json.load(ob) #有參數！！！
    print("I know your favorite number is "+str(con)+".")
def enter_num(file_name):
    while True:
        num_stored()
        read_num(file_name)
        a=input("\nGO ON OR NOT? YES OR NO\n")
        if a!="YES":
            break
file_name=input("where you want to store your number?\n(plz end with'.txt')\n")
mm=num_stored()
while True:
    if mm==0:
        num_stored()
    else:
        enter_num(file_name)
    oo=input("what to stop?YES OR NO")
    if oo!='YES':
        break
        
#10.13 實現
#詢問老名字是否是新用戶的名字，如果不是，提示重新輸入
import json

def username_stored():
    username=input("What's your name?")
    print("Hello! We will remember your name when you come back next time, "+username+"!")
    file_name='hello.txt'
    with open(file_name,'w') as ob:
        json.dump(username,ob)
    return username

def username_out():
    file_name = 'hello.txt'
    with open(file_name) as ob:
        username=json.load(ob)
    return username

def greet_comer():
    old_name=username_out()
    greet=input("Hello! Is "+str(old_name)+" your name?\nY or N\n")
    if greet != 'Y':
        username_stored()
    print(username_out())

greet_comer()
#在另外一個同名文件夾下可以使用上面的函數
#只用greet_comer()就可以
#重構的好處是程序明確便於後期的修改 以及一個特定函數可以不斷嵌套在其他函數裏面 多次使用！
import ha
ha.greet_comer()