I want to create a function, read in a txt file, remove leading space and trailing space for each line, then write to a file, default to overwrite the file I read in, but with option to write to a new file. Here is my code.
def cleanfile(inputfile, outputfile = inputfile):
file1 = open(inputfile,'r')
file2 = open(outputfile, 'w')
lines = list(file1)
newlines = map(lambda x: x.strip(), lines)
newlines = list(newlines)
for i in range(len(newlines)):
file2.write(newlines[i] + '\n')
file1.close()
file2.close()
cleanfile('hw.txt',)
cleanfile('hw.txt','hw_2.txt')
But it give me error. NameError: name 'inputfile' is not defined
How to solve this problem and achieve my goal please? Thank you very much.
standard convention in Python is to use None
as a default and check for that.
def cleanfile(inputfile, outputfile = None):
if outputfile is None:
outputfile = inputfile
file1 = open(inputfile,'r')
file2 = open(outputfile, 'w')
lines = list(file1)
newlines = map(lambda x: x.strip(), lines)
newlines = list(newlines)
for i in range(len(newlines)):
file2.write(newlines[i] + '\n')
file1.close()
file2.close()
cleanfile('hw.txt',)
cleanfile('hw.txt','hw_2.txt')
You can't set outputfile=inputfile as a default parameter. This is a limitation of Python - 'inputfile' doesn't exist as a variable when the default parameter is specified.
You could use a sentinel value:
sentinel = object()
def func(argA, argB=sentinel):
if argB is sentinel:
argB = argA
print (argA, argB)
func("bar") # Prints 'bar bar'
func("bar", None) # Prints 'bar None'
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