Question

我想根据条件打开并读取文件，只有在条件满足时才读取。我写了下面的scriptlet：

def bb(fname, species):
     if species in ('yeast', 'sc'):
         pm =  open('file.txt', 'rU')
         for line in pm:
             line = line.split()
             with open(fname, 'rU') as user:
                 for e in user:
                     e = e.split()
                     if e[0] in line:
                         print(line)
    elif species in ('human', 'hs'):
         pm =  open('file2.txt', 'rU')
         for line in pm:
             line = line.split()
             with open(fname, 'rU') as user:
                 for e in user:
                     e = e.split()
                     if e[0] in line:
                         print(line)

是否有适当的pythonic方式，我不必一遍又一遍地重复/写入相同的行（第3行到第10行）？谢谢！

Answer 1

您可以将文件名值放在变量

中

def bb(fname, species):
    if species in ('yeast', 'sc'):
        fname2 = 'file.txt'
    elif species in ('human', 'hs'):
        fname2 = 'file2.txt'
    else:
        raise ValueError("species received illegal value")

    with  open(fname2, 'rU') as pm:
        for line in pm:
            line = line.split()
            with open(fname, 'rU') as user:
                for e in user:
                    e = e.split()
                    if e[0] in line:
                        print(line)

或定义另一个函数

def bb(fname, species):
    if species in ('yeast', 'sc'):
        read_file('file.txt', fname)
    elif species in ('human', 'hs'):
        read_file('file2.txt', fname)

def read_file(fname1, fname2):
    with  open(fname1, 'rU') as pm:
        for line in pm:
            line = line.split()
            with open(fname2, 'rU') as user:
                for e in user:
                    e = e.split()
                    if e[0] in line:
                        print(line)

Answer 2

既然你似乎在做同样的事情，无论条件如何，你都可以崩溃一切？

def bb(fname, species):
     if species in ['yeast', 'sc', 'human', 'hs']:
         pm =  open('file.txt', 'rU')
         for line in pm:
             line = line.split()
             with open(fname, 'rU') as user:
                 for e in user:
                     e = e.split()
                     if e[0] in line:
                         print(line)

或者你在复制代码时犯了一个错误。如果你想根据具体情况做一些不同的事情，那么你可以创建一个接受该参数的函数，或者首先执行条件语句并使用它来设置某个字符串或值。

E.g。

if species in ('yeast', 'sc'):
    permissions = 'rU'

等

编辑：啊，对于您编辑的问题，答案将如上所述，然后

if species in ('yeast', 'sc'):
    file_name = 'file.txt'
elif species in ('human', 'hs'):
    file_name = 'file2.txt'

Answer 3

只需在if else中打开文件，就可以以类似的方式和相同的代码块完成。

def bb(fname, species):
    if species in ('yeast', 'sc'):
             pm =  open('file.txt', 'rU')
    elif species in ('human', 'hs'):
             pm =  open('file2.txt', 'rU')
         for line in pm:
             line = line.split()
             with open(fname, 'rU') as user:
                 for e in user:
                     e = e.split()
                     if e[0] in line:
                         print(line)

打开条件python文件，但从一个读取数据

3 个答案: