diff options
| -rw-r--r-- | python3.html.markdown | 31 |
1 files changed, 26 insertions, 5 deletions
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] |