打開條件python文件，但從中讀取數據

Question

我想根據條件打開並讀取文件，只有條件符合條件時才能讀取。我寫了下面的腳本：

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) 

是否有正確的pythonic的方法，在這裏我沒有重複/寫同一線（3號線至10）一遍又一遍？謝謝 ！

Answer 1

你可以把文件名值的變量

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) 

或定義另一個函數

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

因爲你似乎不管條件如何的在做同樣的事情，你可以只崩潰一切？

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) 

無論是你還是你犯了一個錯誤複製代碼。如果你想根據情況做一些不同的事情，那麼你可以創建一個接受該參數的函數，或者首先執行條件語句並使用它來設置特定的字符串或值。

E.g.

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

等

---

編輯：啊，你編輯的問題的答案將是如上但隨後

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

Answer 3

只要把文件打開在if else情況下，其餘的將是以類似的方式和相同的代碼塊完成。

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)