London | SDC-Nov-25 | Emiliano Uruena | Sprint 4 | Implement shell Tools Python

implement-shell-tools/cat/cat-python.py

@@ -0,0 +1,42 @@
+import sys
+
+def cat_file(filename, flag):
+    try:
+        with open(filename, 'r') as file:
+            if not flag:
+                for line in file:
+                    print(line, end="")
+
+            elif flag == "-n":
+                for index, line in enumerate(file, start=1):
+                    print(f"{index:6}\t{line}", end="")
+
+            elif flag == "-b":
+                line_number = 1
+                for line in file:
+                    if line.strip() == "":
+                        print(line, end="")
+                    else:
+                        print(f"{line_number:6}\t{line}", end="")
+                        line_number += 1
+
+    except FileNotFoundError:
+        print(f"cat: {filename}: No such file or directory", file=sys.stderr)
+
+def main():
+    args = sys.argv[1:]
+
+    flag = False 
+
+    if "-n" in args:
+        flag = "-n"
+        args.remove("-n")
+    elif "-b" in args:
+        flag = "-b"
+        args.remove("-b")
+
+    for filename in args:
+        cat_file(filename, flag)
+
+if __name__ == "__main__":
+    main()

implement-shell-tools/ls/ls-python.py

@@ -0,0 +1,33 @@
+import sys
+import os
+
+def main():
+    args = sys.argv[1:]
+
+    path = "."
+    one_per_line = False
+    show_hidden = False
+
+    for arg in args:
+        if arg == "-a":
+            show_hidden = True
+        elif arg == "-1":
+            one_per_line = True
+        elif not arg.startswith("-"):
+            path = arg
+
+    entries = os.listdir(path)
+
+    entries.sort()
+
+    if not show_hidden:
+        entries = [f for f in entries if not f.startswith(".")]
+
+    if one_per_line:
+        for entry in entries:
+            print(entry)
+    else:
+        print(" ".join(entries))
+
+if __name__ == "__main__":
+    main()

implement-shell-tools/wc/wc-python.py

@@ -0,0 +1,66 @@
+import sys
+
+def count_file(filename):
+
+    with open(filename, 'r') as file:
+        content = file.read()
+
+    lines = len(content.splitlines())
+    words = len(content.split())
+    chars = len(content)
+
+    return (lines, words, chars)
+
+
+def format_output(lines, words, chars, filename, show_l, show_w, show_c):
+    parts = []
+
+    if show_l:
+        parts.append(f"{lines:8}")
+    if show_w:
+        parts.append(f"{words:8}")
+    if show_c:
+        parts.append(f"{chars:8}")
+
+    parts.append(filename)
+
+    return " ".join(parts)
+
+def main():
+    args = sys.argv[1:]
+
+    l = w = c = False
+    files = []
+
+    for arg in args:
+        if arg == "-l":
+            l = True
+        elif arg == "-w":
+            w = True
+        elif arg == "-c":
+            c = True
+        elif not arg.startswith("-"):
+            files.append(arg)
+
+    if not (l or w or c):
+        l = w = c = True
+
+    total_lines = total_words = total_chars = 0
+    processed_files = 0
+
+    for filename in files:
+        result = count_file(filename)
+        if result:
+            lines, words, chars = result
+            print(format_output(lines, words, chars, filename, l, w, c))
+
+            total_lines += lines
+            total_words += words
+            total_chars += chars
+            processed_files += 1
+
+    if processed_files > 1:
+        print(format_output(total_lines, total_words, total_chars, "total", l, w, c))
+
+if __name__ == "__main__":
+    main()

number-systems/README.md

@@ -5,61 +5,62 @@ Do not convert any binary numbers to decimal when solving a question unless the
 The goal of these exercises is for you to gain an intuition for binary numbers. Using tools to solve the problems defeats the point.
 
 Convert the decimal number 14 to binary.
-Answer:
+Answer: 1110
 
 Convert the binary number 101101 to decimal:
-Answer:
+Answer: 45
 
 Which is larger: 1000 or 0111?
-Answer:
+Answer: 1000
 
 Which is larger: 00100 or 01011?
-Answer:
+Answer: 01011
 
 What is 10101 + 01010?
-Answer:
+Answer:  11111
 
 What is 10001 + 10001?
-Answer:
+Answer:100010
 
 What's the largest number you can store with 4 bits, if you want to be able to represent the number 0?
-Answer:
+Answer: 1111 = 15 (largest representable number)
+        Number of possible values including 0 = 16
 
 How many bits would you need in order to store the numbers between 0 and 255 inclusive?
-Answer:
+Answer: 8 bits
 
 How many bits would you need in order to store the numbers between 0 and 3 inclusive?
-Answer:
+Answer: 2 bits => 00, 01, 10, 11
 
 How many bits would you need in order to store the numbers between 0 and 1000 inclusive?
-Answer:
+Answer: 10 bits
 
 How can you test if a binary number is a power of two (e.g. 1, 2, 4, 8, 16, ...)?
-Answer:
+Answer: Been a binary it would be 1 followed by 0s => 100, 10000, 10
 
 Convert the decimal number 14 to hex.
-Answer:
+Answer:0xE
 
 Convert the decimal number 386 to hex.
-Answer:
+Answer: 0x182
 
 Convert the hex number 386 to decimal.
-Answer:
+Answer: 902
 
 Convert the hex number B to decimal.
-Answer:
+Answer:11
 
 If reading the byte 0x21 as a number, what decimal number would it mean?
-Answer:
+Answer:33
 
 If reading the byte 0x21 as an ASCII character, what character would it mean?
-Answer:
+Answer:!
 
 If reading the byte 0x21 as a greyscale colour, as described in "Approaches for Representing Colors and Images", what colour would it mean?
-Answer:
+Answer: Dark Grey
 
 If reading the bytes 0xAA00FF as an RGB colour, as described in "Approaches for Representing Colors and Images", what colour would it mean?
-Answer:
+Answer:Purple (magenta)
 
 If reading the bytes 0xAA00FF as a sequence of three one-byte decimal numbers, what decimal numbers would they be?
-Answer:
+Answer: 170 0 255