Python 2.7中的文件模式

Question

我正在嘗試使數據庫排序，但是我的r +，w +和a +無法正常工作，我必須關閉文件並以不同的方式再次打開以執行每個操作。 這是有效的代碼，但是當我只用一個文件對象和模式將它們寫為r +或w +或rw +或r + w以及r和a的相同組合時，它不會打印。 它只是寫入文件，但不打印行。

import os;
import sys;

def fileInput(numOfEmployees):
    for i in range(numOfEmployees):
        empId, empFName, empLName, empSalary,  empEmailId = raw_input("Enter employee id: "), raw_input("Enter employee first name: "), raw_input("Enter employee last name: "), raw_input("Enter employee salary: "), raw_input("Enter employee Email ID: ");
        string = empId+" "+empFName+" "+empLName+" "+empSalary+" "+empEmailId+"\n";
        fw.write(string);

def fileSearch(searchStr, fr):
    line = fr.readline();
    while line:
        empId, empFName, empLName, empSalary,  empEmailId = line.split();
        if(searchStr == empFName):
            print line;
        line = fr.readline();


def main():
    numOfEmployees = input("Enter the number of employees: ");
    fileInput(numOfEmployees);
    fw.close();
    searchStr = raw_input("Enter the name of the employee you want to search: ");
    fr = open(string, "r");
    fileSearch(searchStr, fr);
    fr.close();
try:
    string = os.path.dirname(os.path.realpath(__file__))+"/FileIO.txt";
    fw = open(string, "w");
    main();
except KeyboardInterrupt:
    fr.close();
    fw.close();
    sys.exit();

Answer 1

1）如果您使用單個文件句柄（例如fw或fr），請記住在讀取文件時，光標會向下移動文件。 您必須將光標“回滾”到頂部（請參閱seek ）

2）'rw'將覆蓋先前的文件，並從上次運行中刪除先前的條目。 使用“ a +”

嘗試這個：

import os;
import sys;

FileName='FileIO.txt'

def fileInput(fw,numOfEmployees):
    for i in range(numOfEmployees):
        empId, empFName, empLName, empSalary,  empEmailId = raw_input("Enter employee id: "), raw_input("Enter employee first name: "), raw_input("Enter employee last name: "), raw_input("Enter employee salary: "), raw_input("Enter employee Email ID: ");
        string = empId+" "+empFName+" "+empLName+" "+empSalary+" "+empEmailId+"\n";
        fw.write(string);

def fileSearch(fw, searchStr):
    line = fw.readline();
    while line:
        empId, empFName, empLName, empSalary,  empEmailId = line.split();
        if(searchStr == empFName):
            print line;
        line = fw.readline();


def main():

    string = os.path.dirname(os.path.realpath(__file__))+'/'+FileName;

    try:
        fw = open(string, "a+");
    except KeyboardInterrupt:
        sys.exit()

    numOfEmployees = input("Enter the number of employees: ");
    fileInput(fw,numOfEmployees);

    searchStr = raw_input("Enter the name of the employee you want to search: ");
    fw.seek(0)
    fileSearch(fw,searchStr);

    fw.close();

if __name__ == '__main__':
    main()