Python Syntax Problem: Complexity of Comment Syntax and Backslash
this is a example of Python syntax voodoo.
why do i get a syntax error in the following?
# traverse the dir, remove temp files for dpath, dirList, fileList in os.walk(inPath, topdown=False): for ff in fileList: if (ff == ".htaccess") or \ (ff == ".DS_Store") or \ re.search(r"^xx", ff) or \ re.search(r"^#.+#$", ff) or \ # re.search(r"~$", ff) or \ re.search(r"^xx", ff): print("◆", ff)
File "/home/xah/git/xahscripts/make_download_copy/delete_temp_files.py3", line 46 # re.search(r"~$", ff) or \ ^ SyntaxError: invalid syntax
if you remove the comment, then it's fine.
here's the tech answer, given by Wang Bin.
A line ending in a backslash cannot carry a comment. A backslash does not continue a comment. A backslash does not continue a token except for string literals (i.e., tokens other than string literals cannot be split across physical lines using a backslash). A backslash is illegal elsewhere on a line outside a string literal.
Wang also gave this tip:
BTW, I think a more pythonic way to check is:for pattern in (r'^\.htaccess$', r'^\.DS_Store$', r'~$', r'^xx'): if re.search(pattern, ff): print ff
original discussion https://plus.google.com/112757647855302148298/posts/VdV9mKfB8h2
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- Computer Language Design: String Syntax
- What Does it Mean When a Programing Language Claims “Whitespace is Insignificant”?
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