Homework 04: cut.py

homework04/cut.py

@@ -13,8 +13,8 @@ def usage(exit_status: int=0) -> None:
 
 Print selected parts of lines from stream to standard output.
 
-    -d DELIMITER    Use DELIM instead of TAB for field delimiter
-    -f FIELDS       Select only these fields''', file=sys.stderr)
+    -d DELIMITER     Use DELIM instead of TAB for field delimiter
+    -f FIELDS        Select only these fields''', file=sys.stderr)
     sys.exit(exit_status)
 
 def strs_to_ints(strings: list[str]) -> list[int]:
@@ -23,7 +23,13 @@ def strs_to_ints(strings: list[str]) -> list[int]:
     >>> strs_to_ints(['2', '4'])
     [2, 4]
     '''
-    pass
+
+    int_list = []
+
+    for string in strings:
+        int_list.append(int(string))
+
+    return int_list
 
 def cut_line(line: str, delimiter: str='\t', fields: list[int]=[]) -> list[str]:
     ''' Return selected fields from line separated by delimiter.
@@ -31,7 +37,15 @@ def cut_line(line: str, delimiter: str='\t', fields: list[int]=[]) -> list[str]:
     >>> cut_line('Harder, Better, Faster, Stronger', ',', [2, 4])
     [' Better', ' Stronger']
     '''
-    pass
+    
+    parts = line.split(delimiter)
+    selected = []
+    for field in fields:
+        index = field - 1
+        if 0 <= index < len(parts):
+            selected.append(parts[index])
+    
+    return selected
 
 def cut_stream(stream=sys.stdin, delimiter: str='\t', fields: list[int]=[]) -> None:
     ''' Print selected parts of lines from stream to standard output.
@@ -39,7 +53,10 @@ def cut_stream(stream=sys.stdin, delimiter: str='\t', fields: list[int]=[]) -> N
     >>> cut_stream(io.StringIO('Harder, Better, Faster, Stronger'), ',', [2, 4])
      Better, Stronger
     '''
-    pass
+
+    for line in stream:
+        selected = cut_line(line.rstrip(), delimiter, fields)
+        print(*selected, sep=delimiter) # Changed this line
 
 # Main Execution
 
@@ -53,12 +70,31 @@ def main(arguments=sys.argv[1:], stream=sys.stdin) -> None:
      Better, Stronger
     '''
     # Parse command line arguments
-    pass
+    delimiter = '\t'
+    fields = []
+
+    args_iter = iter(arguments)
+    for arg in arguments:
+        if arg == '-h':
+            usage(0)
+        elif arg == '-d':
+            i = arguments.index(arg)
+            if i + 1 < len(arguments):
+                delimiter = arguments[i + 1]
+        elif arg == '-f':
+            i = arguments.index(arg)
+            if i + 1 < len(arguments):
+                fields = strs_to_ints(arguments[i + 1].split(','))
+        elif arg.startswith('-'):
+            usage(1)
+
+    if not fields:
+        usage(1)
 
     # Cut stream with delimiter and fields
-    pass
+    cut_stream(stream, delimiter, fields)
 
 if __name__ == '__main__':
     main()
 
-# vim: set sts=4 sw=4 ts=8 expandtab ft=python:
+# vim: set sts=4 sw=4 ts=8 expandtab ft=python: