From 9a909d6a4a1083a97b54c50de2fb390e76f879c0 Mon Sep 17 00:00:00 2001 From: Steven Basart Date: Sun, 7 Sep 2014 02:39:31 -0400 Subject: Added Boolean operators and lowered line lengths Added Bool operators and and or, and lowered some line lengths. Also shifted some notes above the code lines to keep with same style and help readability. Also added a note on list comprehension. Also added adding to dictionary. --- python3.html.markdown | 31 ++++++++++++++++++++++++++----- 1 file changed, 26 insertions(+), 5 deletions(-) (limited to 'python3.html.markdown') diff --git a/python3.html.markdown b/python3.html.markdown index f6babaff..c3e2ede5 100644 --- a/python3.html.markdown +++ b/python3.html.markdown @@ -61,6 +61,17 @@ False not True # => False not False # => True +# Boolean Operators +# Note "and" and "or" are case-sensitive +True and False #=> False +False or True #=> True + +# Note with ints +0 and 2 #=> 0 +-5 or 0 #=> -5 +0 == False #=> True +2 == True #=> False #only 1 == True #=> True + # Equality is == 1 == 1 # => True 2 == 1 # => False @@ -127,7 +138,8 @@ bool({}) #=> False # Python has a print function print("I'm Python. Nice to meet you!") -# No need to declare variables before assigning to them. Convention is to use lower_case_with_underscores +# No need to declare variables before assigning to them. +# Convention is to use lower_case_with_underscores some_var = 5 some_var # => 5 @@ -176,7 +188,8 @@ li[::-1] # => [3, 4, 2, 1] del li[2] # li is now [1, 2, 3] # You can add lists -li + other_li # => [1, 2, 3, 4, 5, 6] - Note: values for li and for other_li are not modified. +# Note: values for li and for other_li are not modified. +li + other_li # => [1, 2, 3, 4, 5, 6] # Concatenate lists with "extend()" li.extend(other_li) # Now li is [1, 2, 3, 4, 5, 6] @@ -215,14 +228,17 @@ filled_dict = {"one": 1, "two": 2, "three": 3} # Look up values with [] filled_dict["one"] # => 1 -# Get all keys as a list with "keys()". We need to wrap the call in list() because we are getting back an iterable. We'll talk about those later. -list(filled_dict.keys()) # => ["three", "two", "one"] +# Get all keys as a list with "keys()". +# We need to wrap the call in list() because we are getting back an iterable. We'll talk about those later. # Note - Dictionary key ordering is not guaranteed. # Your results might not match this exactly. +list(filled_dict.keys()) # => ["three", "two", "one"] + # Get all values as a list with "values()". Once again we need to wrap it in list() to get it out of the iterable. -list(filled_dict.values()) # => [3, 2, 1] # Note - Same as above regarding key ordering. +list(filled_dict.values()) # => [3, 2, 1] + # Check for existence of keys in a dictionary with "in" "one" in filled_dict # => True @@ -242,6 +258,10 @@ filled_dict.get("four", 4) # => 4 filled_dict.setdefault("five", 5) # filled_dict["five"] is set to 5 filled_dict.setdefault("five", 6) # filled_dict["five"] is still 5 +# Adding to a dictionary +filled_dict.update({"four":4}) #=> {"one": 1, "two": 2, "three": 3, "four": 4} +#filled_dict["four"] = 4 #another way to add to dict + # Remove keys from a dictionary with del del filled_dict["one"] # Removes the key "one" from filled dict @@ -458,6 +478,7 @@ map(add_10, [1, 2, 3]) # => [11, 12, 13] filter(lambda x: x > 5, [3, 4, 5, 6, 7]) # => [6, 7] # We can use list comprehensions for nice maps and filters +# List comprehension stores the output as a list which can itself be a nested list [add_10(i) for i in [1, 2, 3]] # => [11, 12, 13] [x for x in [3, 4, 5, 6, 7] if x > 5] # => [6, 7] -- cgit v1.2.3 From 820eebcd3362841721a981f91695b64af8f50b94 Mon Sep 17 00:00:00 2001 From: Steven Basart Date: Sun, 7 Sep 2014 19:23:07 -0400 Subject: [python3/en] Bool operators Bool operators --- python3.html.markdown | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'python3.html.markdown') diff --git a/python3.html.markdown b/python3.html.markdown index c3e2ede5..a94f4eae 100644 --- a/python3.html.markdown +++ b/python3.html.markdown @@ -66,11 +66,12 @@ not False # => True True and False #=> False False or True #=> True -# Note with ints +# Note using Bool operators with ints 0 and 2 #=> 0 -5 or 0 #=> -5 0 == False #=> True -2 == True #=> False #only 1 == True #=> True +2 == True #=> False +1 == True #=> True # Equality is == 1 == 1 # => True -- cgit v1.2.3