python 脚本中的语法错误

Question

I wrote the following script, which generates a SyntaxError :

#!/usr/bin/python
print "Enter the filename: "
filename = raw_input("> ")
print "Here is your file %r: ", % filename

txt = open(filename)
print txt.read()
txt.close()

Here is the error:

  File "ex02.py", line 4
    print "Here is your file %r: ", % filename
                                    ^
SyntaxError: invalid syntax

How should I fix this?

Answer 1

You can't have a comma there.

print ("Here is your file %r: " % filename),

Answer 2

The coma is not needed, try:

filename = raw_input("> ")
print "Here is your file %r: " % filename

Answer 3

The trouble lies here:

print "Here is your file %r: ", % filename
                              ^

When print finds a comma, it uses that as an argument separator, as can be seen with:

>>> print 1,2
1 2

In that case, the next argument needs to be valid and the sequence % filename is not.

What you undoubtedly meant was:

print "Here is your file %r: " % filename

as per the following transcript:

>>> filename = "whatever"

>>> print "file is %r", % filename
  File "<stdin>", line 1
    print "file is %r", % filename
                        ^
SyntaxError: invalid syntax

>>> print "file is %r" % filename
file is 'whatever'