[英]How does Python's fileinput accept input
我想知道fileinput.input()
如何接受交互式输入。
我在以下位置查看了代码-https: //github.com/python/cpython/blob/master/Lib/fileinput.py
这是内部行读取器的外观:
def _readline(self):
if not self._files:
if 'b' in self._mode:
return b''
else:
return ''
self._filename = self._files[0]
self._files = self._files[1:]
self._startlineno = self.lineno()
self._filelineno = 0
self._file = None
self._isstdin = False
self._backupfilename = 0
if self._filename == '-':
self._filename = '<stdin>'
if 'b' in self._mode:
self._file = getattr(sys.stdin, 'buffer', sys.stdin)
else:
self._file = sys.stdin
self._isstdin = True
else:
if self._inplace:
self._backupfilename = (
os.fspath(self._filename) + (self._backup or ".bak"))
try:
os.unlink(self._backupfilename)
except OSError:
pass
# The next few lines may raise OSError
os.rename(self._filename, self._backupfilename)
self._file = open(self._backupfilename, self._mode)
try:
perm = os.fstat(self._file.fileno()).st_mode
except OSError:
self._output = open(self._filename, "w")
else:
mode = os.O_CREAT | os.O_WRONLY | os.O_TRUNC
if hasattr(os, 'O_BINARY'):
mode |= os.O_BINARY
fd = os.open(self._filename, mode, perm)
self._output = os.fdopen(fd, "w")
try:
if hasattr(os, 'chmod'):
os.chmod(self._filename, perm)
except OSError:
pass
self._savestdout = sys.stdout
sys.stdout = self._output
else:
# This may raise OSError
if self._openhook:
self._file = self._openhook(self._filename, self._mode)
else:
self._file = open(self._filename, self._mode)
self._readline = self._file.readline # hide FileInput._readline
return self._readline()
我不确定该怎么做,也很想知道在这里实际上是如何处理交互式输入的,因为我看不到对内置input()
调用。
实际在fileinput.input()
生成用户提示的是什么?
当不提供任何参数时,它将调用sys.stdin.readline
方法。 如果未提供任何参数,则_readline
方法如下所示。
def _readline(self):
if self._filename == '-': # when no `files` parameter is supplied `self._filename` will be `-`
self._file = sys.stdin
self._readline = self._file.readline # hide FileInput._readline
return self._readline() # invoke the sys.stdin.readline()
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.