Python 如何在csv中逐行保存数据？

最近我有一个项目，就是设计一个登录系统，我必须使用的保存容器是csv。我的问题是，当用户注册新帐户时，我无法逐行保存用户信息。当新用户注册新帐户时，旧帐户的信息将被覆盖和删除

这是我的密码→

#! /usr/bin/env python
#
# GUI module generated by PAGE version 4.9
# In conjunction with Tcl version 8.6
#    Dec 02, 2017 03:27:21 PM
import sys
import csv
import tkMessageBox
try:
    from Tkinter import *
except ImportError:
    from tkinter import *

try:
    import ttk
    py3 = 0
except ImportError:
    import tkinter.ttk as ttk
    py3 = 1


def vp_start_gui():

    global val, w, root
    root = Tk()
    top = New_Toplevel_1 (root)

    root.mainloop()

w = None
def create_New_Toplevel_1(root, *args, **kwargs):

    global w, w_win, rt
    rt = root
    w = Toplevel (root)
    top = New_Toplevel_1 (w)

    return (w, top)

def destroy_New_Toplevel_1():
    global w
    w.destroy()
    w = None


class New_Toplevel_1:
    def __init__(self, top=None):
        '''This class configures and populates the toplevel window.
           top is the toplevel containing window.'''
        _bgcolor = '#d9d9d9'  # X11 color: 'gray85'
        _fgcolor = '#000000'  # X11 color: 'black'
        _compcolor = '#d9d9d9' # X11 color: 'gray85'
        _ana1color = '#d9d9d9' # X11 color: 'gray85'
        _ana2color = '#d9d9d9' # X11 color: 'gray85'
        self.style = ttk.Style()
        if sys.platform == "win32":
            self.style.theme_use('winnative')
        self.style.configure('.',background=_bgcolor)
        self.style.configure('.',foreground=_fgcolor)
        self.style.configure('.',font="TkDefaultFont")
        self.style.map('.',background=
            [('selected', _compcolor), ('active',_ana2color)])

        top.geometry("402x399+496+146")
        top.title("Login Page")
        top.configure(background="#d9d9d9")



        self.Label1 = Label(top)
        self.Label1.place(relx=0.17, rely=0.15, height=22, width=41)
        self.Label1.configure(background="#d9d9d9")
        self.Label1.configure(disabledforeground="#a3a3a3")
        self.Label1.configure(foreground="#000000")
        self.Label1.configure(text='''Name''')

        self.Label2 = Label(top)
        self.Label2.place(relx=0.17, rely=0.25, height=22, width=18)
        self.Label2.configure(background="#d9d9d9")
        self.Label2.configure(disabledforeground="#a3a3a3")
        self.Label2.configure(foreground="#000000")
        self.Label2.configure(text='''ID''')

        self.TEntry1 = ttk.Entry(top)
        self.TEntry1.place(relx=0.4, rely=0.15, relheight=0.06, relwidth=0.36)
        self.TEntry1.configure(takefocus="")
        self.TEntry1.configure(cursor="ibeam")

        self.TEntry2 = ttk.Entry(top)
        self.TEntry2.place(relx=0.4, rely=0.25, relheight=0.06, relwidth=0.36)
        self.TEntry2.configure(takefocus="")
        self.TEntry2.configure(cursor="ibeam")

        self.Label3 = Label(top)
        self.Label3.place(relx=0.17, rely=0.35, height=22, width=57)
        self.Label3.configure(background="#d9d9d9")
        self.Label3.configure(disabledforeground="#a3a3a3")
        self.Label3.configure(foreground="#000000")
        self.Label3.configure(text='''Password''')
        self.Label3.configure(width=57)

        self.TEntry3 = ttk.Entry(top,show="*")
        self.TEntry3.place(relx=0.4, rely=0.35, relheight=0.06, relwidth=0.36)
        self.TEntry3.configure(takefocus="")
        self.TEntry3.configure(cursor="ibeam")

        self.Button1 = Button(top,command=self.regist)
        self.Button1.place(relx=0.17, rely=0.64, height=46, width=88)
        self.Button1.configure(activebackground="#d9d9d9")
        self.Button1.configure(activeforeground="#000000")
        self.Button1.configure(background="#d9d9d9")
        self.Button1.configure(disabledforeground="#a3a3a3")
        self.Button1.configure(foreground="#000000")
        self.Button1.configure(highlightbackground="#d9d9d9")
        self.Button1.configure(highlightcolor="black")
        self.Button1.configure(pady="0")
        self.Button1.configure(text='''Sign up''')
        self.Button1.configure(width=88)

        self.Button2 = Button(top,command=self.check)
        self.Button2.place(relx=0.62, rely=0.64, height=46, width=88)
        self.Button2.configure(activebackground="#d9d9d9")
        self.Button2.configure(activeforeground="#000000")
        self.Button2.configure(background="#d9d9d9")
        self.Button2.configure(disabledforeground="#a3a3a3")
        self.Button2.configure(foreground="#000000")
        self.Button2.configure(highlightbackground="#d9d9d9")
        self.Button2.configure(highlightcolor="black")
        self.Button2.configure(pady="0")
        self.Button2.configure(text='''Login''')
        self.Button2.configure(width=88)

    def check(self):
        import csv
        f=open("example.csv","r")
        q=csv.reader(f)
        l=list(q)
        #print l
        if len(self.TEntry1.get())==0 and len(self.TEntry2.get())==0 and len(self.TEntry3.get())==0:
            tkMessageBox.showinfo("Error","somewhere is empty")
        if (self.TEntry1.get()==l[0][0] and self.TEntry2.get()==l[0][2] and self.TEntry3.get()==l[0][4]) and (len(self.TEntry1.get())!=0 and len(self.TEntry2.get())!=0 and len(self.TEntry3.get())!=0):
            tkMessageBox.showinfo("Success", "Hi!!  "+str(self.TEntry1.get()))
        elif len(self.TEntry1.get())!=0 and len(self.TEntry2.get())!=0 and len(self.TEntry3.get())!=0:
            tkMessageBox.showinfo("Fail", "Sorry!! You are not  " + str(self.TEntry1.get()))
    def regist(self):
        root.destroy()
        #root.attributes('-fullscreen', True)
        #New_Toplevel_2()
        vp_start_gui2()
def vp_start_gui2():

    global val2, w2, root2
    root2 = Tk()
    top2 = New_Toplevel_2 (root2)

    root2.mainloop()

w2 = None
def create_New_Toplevel_2(root2, *args, **kwargs):

    global w2, w_win2, rt2
    rt2 = root2
    w2 = Toplevel (root2)
    top2 = New_Toplevel_2 (w2)

    return (w2, top2)

def destroy_New_Toplevel_2():
    global w2
    w2.destroy()
    w2 = None

class New_Toplevel_2:
    def __init__(self, top=None):
        '''This class configures and populates the toplevel window.
           top is the toplevel containing window.'''
        _bgcolor = '#d9d9d9'  # X11 color: 'gray85'
        _fgcolor = '#000000'  # X11 color: 'black'
        _compcolor = '#d9d9d9' # X11 color: 'gray85'
        _ana1color = '#d9d9d9' # X11 color: 'gray85'
        _ana2color = '#d9d9d9' # X11 color: 'gray85'
        self.style = ttk.Style()
        if sys.platform == "win32":
            self.style.theme_use('winnative')
        self.style.configure('.',background=_bgcolor)
        self.style.configure('.',foreground=_fgcolor)
        self.style.configure('.',font="TkDefaultFont")
        self.style.map('.',background=
            [('selected', _compcolor), ('active',_ana2color)])

        top.geometry("445x524+471+129")
        top.title("Sing up")
        top.configure(background="#d9d9d9")



        self.Label1 = Label(top)
        self.Label1.place(relx=0.2, rely=0.15, height=22, width=41)
        self.Label1.configure(background="#d9d9d9")
        self.Label1.configure(disabledforeground="#a3a3a3")
        self.Label1.configure(foreground="#000000")
        self.Label1.configure(text='''Name''')

        self.Label2 = Label(top)
        self.Label2.place(relx=0.2, rely=0.23, height=22, width=37)
        self.Label2.configure(background="#d9d9d9")
        self.Label2.configure(disabledforeground="#a3a3a3")
        self.Label2.configure(foreground="#000000")
        self.Label2.configure(text='''Email''')

        self.Label3 = Label(top)
        self.Label3.place(relx=0.19, rely=0.31, height=22, width=48)
        self.Label3.configure(background="#d9d9d9")
        self.Label3.configure(disabledforeground="#a3a3a3")
        self.Label3.configure(foreground="#000000")
        self.Label3.configure(text='''Gender''')

        self.Label4 = Label(top)
        self.Label4.place(relx=0.18, rely=0.38, height=22, width=67)
        self.Label4.configure(background="#d9d9d9")
        self.Label4.configure(disabledforeground="#a3a3a3")
        self.Label4.configure(foreground="#000000")
        self.Label4.configure(text='''WatchID''')
        self.Label4.configure(width=67)

        self.Radiobutton1 = Radiobutton(top)
        self.Radiobutton1.place(relx=0.43, rely=0.31, relheight=0.05
                , relwidth=0.14)
        self.Radiobutton1.configure(activebackground="#d9d9d9")
        self.Radiobutton1.configure(activeforeground="#000000")
        self.Radiobutton1.configure(background="#d9d9d9")
        self.Radiobutton1.configure(disabledforeground="#a3a3a3")
        self.Radiobutton1.configure(foreground="#000000")
        self.Radiobutton1.configure(highlightbackground="#d9d9d9")
        self.Radiobutton1.configure(highlightcolor="black")
        self.Radiobutton1.configure(justify=LEFT)
        self.Radiobutton1.configure(text='''Male''')

        self.Radiobutton2 = Radiobutton(top)
        self.Radiobutton2.place(relx=0.62, rely=0.31, relheight=0.05
                , relwidth=0.14)
        self.Radiobutton2.configure(activebackground="#d9d9d9")
        self.Radiobutton2.configure(activeforeground="#000000")
        self.Radiobutton2.configure(background="#d9d9d9")
        self.Radiobutton2.configure(disabledforeground="#a3a3a3")
        self.Radiobutton2.configure(foreground="#000000")
        self.Radiobutton2.configure(highlightbackground="#d9d9d9")
        self.Radiobutton2.configure(highlightcolor="black")
        self.Radiobutton2.configure(justify=LEFT)
        self.Radiobutton2.configure(text='''Female''')

        self.Button1 = Button(top,command=self.re)
        self.Button1.place(relx=0.56, rely=0.68, height=46, width=88)
        self.Button1.configure(activebackground="#d9d9d9")
        self.Button1.configure(activeforeground="#000000")
        self.Button1.configure(background="#d9d9d9")
        self.Button1.configure(disabledforeground="#a3a3a3")
        self.Button1.configure(foreground="#000000")
        self.Button1.configure(highlightbackground="#d9d9d9")
        self.Button1.configure(highlightcolor="black")
        self.Button1.configure(pady="0")
        self.Button1.configure(text='''Register''')
        self.Button1.configure(width=88)

        self.Label5 = Label(top)
        self.Label5.place(relx=0.21, rely=0.46, height=22, width=37)
        self.Label5.configure(background="#d9d9d9")
        self.Label5.configure(disabledforeground="#a3a3a3")
        self.Label5.configure(foreground="#000000")
        self.Label5.configure(text='''Age''')

        self.TEntry1 = ttk.Entry(top)
        self.TEntry1.place(relx=0.42, rely=0.15, relheight=0.04, relwidth=0.33)
        self.TEntry1.configure(takefocus="")
        self.TEntry1.configure(cursor="ibeam")

        self.TEntry2 = ttk.Entry(top)
        self.TEntry2.place(relx=0.42, rely=0.23, relheight=0.04, relwidth=0.33)
        self.TEntry2.configure(takefocus="")
        self.TEntry2.configure(cursor="ibeam")

        self.TEntry3 = ttk.Entry(top)
        self.TEntry3.place(relx=0.42, rely=0.38, relheight=0.04, relwidth=0.33)
        self.TEntry3.configure(takefocus="")
        self.TEntry3.configure(cursor="ibeam")

        self.TEntry4 = ttk.Entry(top)
        self.TEntry4.place(relx=0.42, rely=0.46, relheight=0.04, relwidth=0.33)
        self.TEntry4.configure(takefocus="")
        self.TEntry4.configure(cursor="ibeam")

        self.Label6 = Label(top)
        self.Label6.place(relx=0.19, rely=0.54, height=22, width=57)
        self.Label6.configure(background="#d9d9d9")
        self.Label6.configure(disabledforeground="#a3a3a3")
        self.Label6.configure(foreground="#000000")
        self.Label6.configure(text='''Password''')
        self.Label6.configure(width=57)

        self.TEntry5 = ttk.Entry(top,show="*")
        self.TEntry5.place(relx=0.42, rely=0.55, relheight=0.04, relwidth=0.33)
        self.TEntry5.configure(takefocus="")
        self.TEntry5.configure(cursor="ibeam")

    def re(self):
        import csv
        d1 = str(self.TEntry1.get())
        d2 = str(self.TEntry2.get())
        d3 = str(self.TEntry3.get())
        d4 = str(self.TEntry4.get())
        d5 = str(self.TEntry5.get())
        dict={"Name":str(self.TEntry1.get()),"Email":str(self.TEntry2.get()),"WatchID":str(self.TEntry3.get()),"Age":str(self.TEntry4.get()),"Password":str(self.TEntry5.get())}
        info=[dict["Name"],dict["Email"],dict["WatchID"],dict["Age"],dict["Password"]]
        f = open('example.csv', 'w')
        w = csv.writer(f)
        w.writerow(info)
        f.flush()
        f.close()
        root2.destroy()
        vp_start_gui()

if __name__ == '__main__':
    #App=New_Toplevel_1()
    vp_start_gui()
    #vp_start_gui2()

主要保存块是New_Toplevel_2类中的def re（self），这就是我最近保存数据的方式。它仍然有效，但不太好

---

有人能帮我解决这个问题吗？

我想你应该换线：

f = open('example.csv', 'w')

到

---

w

会在文件打开时截断文件，以便每次删除现有数据

a

意味着在文件末尾追加并放置新行。

f=open（'example.csv'，'a'）

哇，它真管用！我没有意识到这个简单的问题，非常感谢！！谢谢！！我不知道这么简单的问题。谢谢大家改进了答案@史蒂文·阿尔梅罗斯

f = open('example.csv', 'a')