common patterns

kyclark · kyclark · commit e646e196c460 · 2019-05-17T13:16:04.000-07:00
diff --git a/appendix/examples/.gitignore b/appendix/examples/.gitignore
@@ -0,0 +1 @@
+out.txt
diff --git a/appendix/examples/args.py b/appendix/examples/args.py
@@ -0,0 +1,9 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+args = sys.argv[1:]
+num = len(args)
+
+print('There are {} arg{}'.format(num, '' if num == 1 else 's'))
diff --git a/appendix/examples/codons.py b/appendix/examples/codons.py
@@ -0,0 +1,19 @@
+#!/usr/bin/env python3
+"""Extract codons from DNA"""
+
+import os
+import sys
+
+args = sys.argv[1:]
+num_args = len(args)
+
+if not 1 <= num_args <= 2:
+    print('Usage: {} DNA'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+string = args[0]
+k = 3
+n = len(string) - k + 1
+
+for i in range(0, n, k):
+    print(string[i:i+k])
diff --git a/appendix/examples/create_dir.py b/appendix/examples/create_dir.py
@@ -0,0 +1,19 @@
+#!/usr/bin/env python3
+"""Test for a directory and create if needed"""
+
+import os
+import sys
+
+args = sys.argv[1:]
+
+if len(args) != 1:
+    print('Usage: {} DIR'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+dirname = args[0]
+
+if os.path.isdir(dirname):
+    print('"{}" exists'.format(dirname))
+else:
+    print('Creating "{}"'.format(dirname))
+    os.makedirs(dirname)
diff --git a/appendix/examples/default_arg.py b/appendix/examples/default_arg.py
@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+args = sys.argv[1:]
+num_args = len(args)
+
+if not 1 <= num_args <= 2:
+    print('Usage: {} FILE [NUM]'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+file = args[0]
+num = args[1] if num_args == 2 else 10
+
+print('FILE is "{}", NUM is "{}"'.format(file, num))
diff --git a/appendix/examples/kmers.py b/appendix/examples/kmers.py
@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+"""Extract k-mers from string"""
+
+import os
+import sys
+
+args = sys.argv[1:]
+num_args = len(args)
+
+if not 1 <= num_args <= 2:
+    print('Usage: {} STR [K]'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+string = args[0]
+k = args[1] if num_args == 2 else '3'
+
+# Guard against a string like "foo"
+if not k.isdigit():
+    print('k "{}" is not a digit'.format(k))
+    sys.exit(1)
+
+# Safe to convert now
+k = int(k)
+
+if len(string) < k:
+    print('There are no {}-length substrings in "{}"'.format(k, string))
+else:
+    n = len(string) - k + 1
+    for i in range(0, n):
+        print(string[i:i+k])
diff --git a/appendix/examples/list_dir.py b/appendix/examples/list_dir.py
@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+"""Show contents of directory argument"""
+
+import os
+import sys
+
+args = sys.argv[1:]
+
+if len(args) != 1:
+    print('Usage: {} DIR'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+dirname = args[0]
+
+if not os.path.isdir(dirname):
+    print('"{}" is not a directory'.format(dirname), file=sys.stderr)
+    sys.exit(1)
+
+for entry in os.listdir(dirname):
+    print(entry)
diff --git a/appendix/examples/name_args.py b/appendix/examples/name_args.py
@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+args = sys.argv[1:]
+
+if len(args) != 2:
+    print('Usage: {} FILE NUM'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+file, num = args
+
+file = args[0]
+num = args[1]
+
+print('FILE is "{}", NUM is "{}"'.format(file, num))
diff --git a/appendix/examples/nobody.txt b/appendix/examples/nobody.txt
@@ -0,0 +1,11 @@
+I’m Nobody! Who are you?
+Are you – Nobody – too?
+Then there’s a pair of us!
+Don’t tell! they’d advertise – you know!
+
+How dreary – to be – Somebody!
+How public – like a Frog –  
+To tell one’s name – the livelong June –  
+To an admiring Bog!
+
+Emily Dickinson
diff --git a/appendix/examples/read_file.py b/appendix/examples/read_file.py
@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+"""Read a file argument"""
+
+import os
+import sys
+
+args = sys.argv[1:]
+
+if len(args) != 1:
+    print('Usage: {} FILE'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+filename = args[0]
+
+if not os.path.isfile(filename):
+    print('"{}" is not a file'.format(filename), file=sys.stderr)
+    sys.exit(1)
+
+for line in open(filename):
+    print(line, end='')
diff --git a/appendix/examples/skip_loop.py b/appendix/examples/skip_loop.py
@@ -0,0 +1,25 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+
+args = sys.argv[1:]
+
+if len(args) != 1:
+    print('Usage: {} FILE'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+file = args[0]
+
+if not os.path.isfile(file):
+    print('"{}" is not a file'.format(file), file=sys.stderr)
+    sys.exit(1)
+
+for i, line in enumerate(open(file)):
+    if (i + 1) % 2 == 0:
+        continue
+
+    print(i + 1, line, end='')
+
+print('i = ', i)
diff --git a/appendix/examples/sort_dict_by_keys.py b/appendix/examples/sort_dict_by_keys.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+albums = {
+    "2112": 1976,
+    "A Farewell To Kings": 1977,
+    "All the World's a Stage": 1976,
+    "Caress of Steel": 1975,
+    "Exit, Stage Left": 1981,
+    "Fly By Night": 1975,
+    "Grace Under Pressure": 1984,
+    "Hemispheres": 1978,
+    "Hold Your Fire": 1987,
+    "Moving Pictures": 1981,
+    "Permanent Waves": 1980,
+    "Power Windows": 1985,
+    "Signals": 1982,
+}
+
+for album in sorted(albums.keys()):
+    print('{:25} {}'.format(album, albums[album]))
diff --git a/appendix/examples/sort_dict_by_keys2.py b/appendix/examples/sort_dict_by_keys2.py
@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+albums = {
+    "2112": 1976,
+    "A Farewell To Kings": 1977,
+    "All the World's a Stage": 1976,
+    "Caress of Steel": 1975,
+    "Exit, Stage Left": 1981,
+    "Fly By Night": 1975,
+    "Grace Under Pressure": 1984,
+    "Hemispheres": 1978,
+    "Hold Your Fire": 1987,
+    "Moving Pictures": 1981,
+    "Permanent Waves": 1980,
+    "Power Windows": 1985,
+    "Signals": 1982,
+}
+
+for album, year in sorted(albums.items()):
+    print('{:25} {}'.format(album, year))
diff --git a/appendix/examples/sort_dict_by_values.py b/appendix/examples/sort_dict_by_values.py
@@ -0,0 +1,27 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+albums = {
+    "2112": 1976,
+    "A Farewell To Kings": 1977,
+    "All the World's a Stage": 1976,
+    "Caress of Steel": 1975,
+    "Exit, Stage Left": 1981,
+    "Fly By Night": 1975,
+    "Grace Under Pressure": 1984,
+    "Hemispheres": 1978,
+    "Hold Your Fire": 1987,
+    "Moving Pictures": 1981,
+    "Permanent Waves": 1980,
+    "Power Windows": 1985,
+    "Signals": 1982,
+}
+
+# Create a list of (value, key) tuples 
+# sorted in descending order by the values
+pairs = sorted([(x[1], x[0]) for x in albums.items()])
+
+for year, album in pairs:
+    print('{} {}'.format(year, album))
diff --git a/appendix/examples/unpack_dict.py b/appendix/examples/unpack_dict.py
@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+"""Unpack dict"""
+
+import os
+import sys
+
+albums = {
+    "2112": 1976,
+    "A Farewell To Kings": 1977,
+    "All the World's a Stage": 1976,
+    "Caress of Steel": 1975,
+    "Exit, Stage Left": 1981,
+    "Fly By Night": 1975,
+    "Grace Under Pressure": 1984,
+    "Hemispheres": 1978,
+    "Hold Your Fire": 1987,
+    "Moving Pictures": 1981,
+    "Permanent Waves": 1980,
+    "Power Windows": 1985,
+    "Signals": 1982,
+}
+
+for tup in albums.items():
+    album = tup[0]
+    year = tup[1]
+    print('{:4} {}'.format(year, album))
diff --git a/appendix/examples/unpack_dict2.py b/appendix/examples/unpack_dict2.py
@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+"""Unpack dict"""
+
+import os
+import sys
+
+albums = {
+    "2112": 1976,
+    "A Farewell To Kings": 1977,
+    "All the World's a Stage": 1976,
+    "Caress of Steel": 1975,
+    "Exit, Stage Left": 1981,
+    "Fly By Night": 1975,
+    "Grace Under Pressure": 1984,
+    "Hemispheres": 1978,
+    "Hold Your Fire": 1987,
+    "Moving Pictures": 1981,
+    "Permanent Waves": 1980,
+    "Power Windows": 1985,
+    "Signals": 1982,
+}
+
+for album, year in albums.items():
+    print('{:4} {}'.format(year, album))
diff --git a/appendix/examples/upper_list.py b/appendix/examples/upper_list.py
@@ -0,0 +1,16 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+args = sys.argv[1:]
+
+if len(args) < 1:
+    print('Usage: {} ARG [ARG...]'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+print('List comprehension')
+print(', '.join([x.upper() for x in args]))
+
+print('Map')
+print(', '.join(map(str.upper, args)))
diff --git a/appendix/examples/write_file.py b/appendix/examples/write_file.py
@@ -0,0 +1,20 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+
+args = sys.argv[1:]
+
+if len(args) < 1:
+    print('Usage: {} ARG1 [ARG2...]'.format(os.path.basename(sys.argv[0])))
+    sys.exit(1)
+
+outfile = 'out.txt'
+out_fh = open(outfile, 'wt')
+
+for arg in args:
+    out_fh.write(arg + '\n')
+
+out_fh.close()
+print('Done, see "{}"'.format(outfile))
diff --git a/appendix/howto.md b/appendix/howto.md
