追加到每個打印消息

Question

簡單的問題，我想文本追加到每print我打電話的前面，例如，如果我的文字設置爲hello，跑這樣的：

這將打印此：

hellohello there 
hello hi again 

是否有這樣做的任何方式，而不使用函數來使用，而不是print？

Answer 1

您可以覆蓋打印按DevPlayer's post here on StackOverflow，在這裏略作修改：

from __future__ import print_function 
# Note: If you are using Python 3 leave this line out 
# This must be the first statement before other statements. 
# You may only put a quoted or triple quoted string, 
# Python comments or blank lines before the __future__ line. 
import sys 

def print(*args, **kwargs): 
    """My custom print() function.""" 
    # Adding new arguments to the print function signature 
    # is probably a bad idea. 
    # Instead consider testing if custom argument keywords 
    # are present in kwargs 
    sys.stdout.write('hello') 
    return __builtins__.print(*args, **kwargs) 

print ("hello there") 
print (" hi again") 

[編輯] ...或DSM建議，你可以避開與此SYS電話：

from __future__ import print_function 
# Note: If you are using Python 3 leave this line out 
# This must be the first statement before other statements. 
# You may only put a quoted or triple quoted string, 
# Python comments or blank lines before the __future__ line. 

def print(*args, **kwargs): 
    """My custom print() function.""" 
    # Adding new arguments to the print function signature 
    # is probably a bad idea. 
    # Instead consider testing if custom argument keywords 
    # are present in kwargs 
    __builtins__.print('hello',end='') 
    return __builtins__.print(*args, **kwargs) 

print ("hello there") 
print (" hi again") 

Answer 2

您無法更改Python 2的打印語句，但可以編寫自己的文件類對象並使用它：

class PrefixedFile(object): 
    def __init__(self, f, prefix): 
     self.f = f 
     self.prefix = prefix 

    def write(self, s): 
     s = s.replace("\n", "\n"+self.prefix) 
     self.f.write(s) 

sys.stdout = PrefixedFile(sys.stdout, "hello: ") 

print "One" 
print "Two" 

請注意，此代碼不起作用，因爲它在第一行中缺少前綴，並在最後添加了一個前綴，但您明白了！ :)

Answer 3

儘管喬恩·凱奇的回答是更換print()功能的一個很好的方式，我會建議，而不是使用自己的打印功能（使用喬恩的代碼）：

from __future__ import print_function 
# Note: If you are using Python 3 leave this line out 
# This must be the first statement before other statements. 
# You may only put a quoted or triple quoted string, 
# Python comments or blank lines before the __future__ line. 

def my_print(*args, **kwargs): 
    """My custom print() function.""" 
    # Adding new arguments to the print function signature 
    # is probably a bad idea. 
    # Instead consider testing if custom argument keywords 
    # are present in kwargs 
    print('hello', end='') 
    print(*args, **kwargs) 

與喬恩的答案唯一的區別是你不覆蓋內置的print()（「猴子修補」）。我提倡這一點，而不是修改print()，因爲這會讓您的代碼更易於維護，因爲每個人都期望print()是內置的。

使用print()功能代替print聲明，my_print()，給人greater flexibility。