Question

我正在尝试使数据库排序，但是我的r +，w +和a +无法正常工作，我必须关闭文件并以不同的方式再次打开以执行每个操作。这是有效的代码，但是当我只用一个文件对象和模式将它们写为r +或w +或rw +或r + w以及r和a的相同组合时，它不会打印。它只是写入文件，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）如果使用单个文件句柄（例如fw或fr），请记住在读取文件时，光标会向下移动文件。您必须将光标“回滚”到顶部（请参见seek）

2）'rw'将覆盖先前的文件，并从上次运行中删除先前的条目。使用'a +'

尝试一下：

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()

Python 2.7中的文件模式

1 个答案: