python - 在 python 中使用 "w"模式有什么意义？

Question

#From the sys package, i'm importing the argv
from sys import argv
#Un packaging the arguments
script, filename = argv 
#Print statements
print "We're going to erase %r." % filename
print "If you don't want that, hit CTRL-C (^C)."
print "If you do want that, hit RETURN."
#To accept whether or not we want to continue or not
raw_input("?")

print "Opening the file..."
# I am opening the file
target = open(filename)

print "Truncating the file. Goodbye!"
target.truncate()

print "Now i'm going to ask you for three lines."

line1 = raw_input("line 1: ")
line2 = raw_input("line 2: ")
line3 = raw_input("line 3: ")

print "I'm going to write these to the file."
x = "%r\n %r\n %r\n" % (line1, line2, line3)
target.write(x)
#This also works to write the files
# target.write ("%r\n%r\n%r\n" % (line1, line2, line3))

print "And finally, we close it."
target.close()

对于 open(filename)，我发现当我将脚本付诸行动时得到的结果与 open(filename "w")

相同

那么“w”有什么意义呢？因为我已经有了使用 target.write() 命令写入的函数!

Answer 1

“w”模式如果文件不存在则创建文件，如果存在则清空它。