Tutorial by Examples: f

The preferred method of file i/o is to use the with keyword. This will ensure the file handle is closed once the reading or writing has been completed. with open('myfile.txt') as in_file: content = in_file.read() print(content) or, to handle closing the file manually, you can forgo with...

with open('myfile.txt', 'w') as f: f.write("Line 1") f.write("Line 2") f.write("Line 3") f.write("Line 4") If you open myfile.txt, you will see that its contents are: Line 1Line 2Line 3Line 4 Python doesn't automatically add line b...

with open(input_file, 'r') as in_file, open(output_file, 'w') as out_file: for line in in_file: out_file.write(line) Using the shutil module: import shutil shutil.copyfile(src, dst)

This a Basic example for using the MVVM model in a windows desktop application, using WPF and C#. The example code implements a simple "user info" dialog. The View The XAML <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto"/> ...

import json d = { 'foo': 'bar', 'alice': 1, 'wonderland': [1, 2, 3] } json.dumps(d) The above snippet will return the following: '{"wonderland": [1, 2, 3], "foo": "bar", "alice": 1}'

import json s = '{"wonderland": [1, 2, 3], "foo": "bar", "alice": 1}' json.loads(s) The above snippet will return the following: {u'alice': 1, u'foo': u'bar', u'wonderland': [1, 2, 3]}

The following snippet encodes the data stored in d into JSON and stores it in a file (replace filename with the actual name of the file). import json d = { 'foo': 'bar', 'alice': 1, 'wonderland': [1, 2, 3] } with open(filename, 'w') as f: json.dump(d, f)

The following snippet opens a JSON encoded file (replace filename with the actual name of the file) and returns the object that is stored in the file. import json with open(filename, 'r') as f: d = json.load(f)

git diff This will show the unstaged changes on the current branch from the commit before it. It will only show changes relative to the index, meaning it shows what you could add to the next commit, but haven't. To add (stage) these changes, you can use git add. If a file is staged, but was modi...

git diff --staged This will show the changes between the previous commit and the currently staged files. NOTE: You can also use the following commands to accomplish the same thing: git diff --cached Which is just a synonym for --staged or git status -v Which will trigger the verbose sett...

You can upvote (or downvote, if you want...) examples you created. Although you won't get any reputation for doing so, upvoting your the example will influence the examples' ordering on the page. Any previous contributors to the examples will get reputation. On the other hand, you might consider ...

Python's string type provides many functions that act on the capitalization of a string. These include : str.casefold str.upper str.lower str.capitalize str.title str.swapcase With unicode strings (the default in Python 3), these operations are not 1:1 mappings or reversible. Most of thes...

str.split(sep=None, maxsplit=-1) str.split takes a string and returns a list of substrings of the original string. The behavior differs depending on whether the sep argument is provided or omitted. If sep isn't provided, or is None, then the splitting takes place wherever there is whitespace. Howe...

Python's str type also has a method for replacing occurences of one sub-string with another sub-string in a given string. For more demanding cases, one can use re.sub. str.replace(old, new[, count]): str.replace takes two arguments old and new containing the old sub-string which is to be replace...

A generator function is created with a function* declaration. When it is called, its body is not immediately executed. Instead, it returns a generator object, which can be used to "step through" the function's execution. A yield expression inside the function body defines a point at which...

Array is an ordered collection type in the Swift standard library. It provides O(1) random access and dynamic reallocation. Array is a generic type, so the type of values it contains are known at compile time. As Array is a value type, its mutability is defined by whether it is annotated as a var (...

Determine whether an array is empty or return its size var exampleArray = [1,2,3,4,5] exampleArray.isEmpty //false exampleArray.count //5 Reverse an Array Note: The result is not performed on the array the method is called on and must be put into its own variable. exampleArray = exampleArray...

There are multiple ways to append values onto an array var exampleArray = [1,2,3,4,5] exampleArray.append(6) //exampleArray = [1, 2, 3, 4, 5, 6] var sixOnwards = [7,8,9,10] exampleArray += sixOnwards //exampleArray = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] and remove values from an array exampleAr...

One of the most commonly used events is waiting for the document to have loaded, including both script files and images. The load event on document is used for this. document.addEventListener('load', function() { console.log("Everything has now loaded!"); }); Sometimes you try to ...

By default, attempting to lookup the value for a key which does not exist will return nil. You can optionally specify some other value to return (or an action to take) when the hash is accessed with a non-existent key. Although this is referred to as "the default value", it need not be a s...