File "<ipython-input-28-672ad970f03b>", line 1 1variable = 2 ^SyntaxError: invalid syntax
fileDescriptor=open("example.txt","wt")fileDescriptor.write("This is a text example")fileDescriptor.close()
Help on built-in function open in module io:
open(file, mode='r', buffering=-1, encoding=None, errors=None, newline=None, closefd=True, opener=None)
Open file and return a stream. Raise IOError upon failure.
file is either a text or byte string giving the name (and the path
if the file isn't in the current working directory) of the file to
be opened or an integer file descriptor of the file to be
wrapped. (If a file descriptor is given, it is closed when the
returned I/O object is closed, unless closefd is set to False.)
mode is an optional string that specifies the mode in which the file
is opened. It defaults to 'r' which means open for reading in text
mode. Other common values are 'w' for writing (truncating the file if
it already exists), 'x' for creating and writing to a new file, and
'a' for appending (which on some Unix systems, means that all writes
append to the end of the file regardless of the current seek position).
In text mode, if encoding is not specified the encoding used is platform
dependent: locale.getpreferredencoding(False) is called to get the
current locale encoding. (For reading and writing raw bytes use binary
mode and leave encoding unspecified.) The available modes are:
'r' open for reading (default)
'w' open for writing, truncating the file first
'x' create a new file and open it for writing
'a' open for writing, appending to the end of the file if it exists
'b' binary mode
't' text mode (default)
'+' open a disk file for updating (reading and writing)
'U' universal newline mode (deprecated)
The default mode is 'rt' (open for reading text). For binary random
access, the mode 'w+b' opens and truncates the file to 0 bytes, while
'r+b' opens the file without truncation. The 'x' mode implies 'w' and
raises an `FileExistsError` if the file already exists.
Python distinguishes between files opened in binary and text modes,
even when the underlying operating system doesn't. Files opened in
binary mode (appending 'b' to the mode argument) return contents as
bytes objects without any decoding. In text mode (the default, or when
't' is appended to the mode argument), the contents of the file are
returned as strings, the bytes having been first decoded using a
platform-dependent encoding or using the specified encoding if given.
'U' mode is deprecated and will raise an exception in future versions
of Python. It has no effect in Python 3. Use newline to control
universal newlines mode.
buffering is an optional integer used to set the buffering policy.
Pass 0 to switch buffering off (only allowed in binary mode), 1 to select
line buffering (only usable in text mode), and an integer > 1 to indicate
the size of a fixed-size chunk buffer. When no buffering argument is
given, the default buffering policy works as follows:
* Binary files are buffered in fixed-size chunks; the size of the buffer
is chosen using a heuristic trying to determine the underlying device's
"block size" and falling back on `io.DEFAULT_BUFFER_SIZE`.
On many systems, the buffer will typically be 4096 or 8192 bytes long.
* "Interactive" text files (files for which isatty() returns True)
use line buffering. Other text files use the policy described above
for binary files.
encoding is the name of the encoding used to decode or encode the
file. This should only be used in text mode. The default encoding is
platform dependent, but any encoding supported by Python can be
passed. See the codecs module for the list of supported encodings.
errors is an optional string that specifies how encoding errors are to
be handled---this argument should not be used in binary mode. Pass
'strict' to raise a ValueError exception if there is an encoding error
(the default of None has the same effect), or pass 'ignore' to ignore
errors. (Note that ignoring encoding errors can lead to data loss.)
See the documentation for codecs.register or run 'help(codecs.Codec)'
for a list of the permitted encoding error strings.
newline controls how universal newlines works (it only applies to text
mode). It can be None, '', '\n', '\r', and '\r\n'. It works as
* On input, if newline is None, universal newlines mode is
enabled. Lines in the input can end in '\n', '\r', or '\r\n', and
these are translated into '\n' before being returned to the
caller. If it is '', universal newline mode is enabled, but line
endings are returned to the caller untranslated. If it has any of
the other legal values, input lines are only terminated by the given
string, and the line ending is returned to the caller untranslated.
* On output, if newline is None, any '\n' characters written are
translated to the system default line separator, os.linesep. If
newline is '' or '\n', no translation takes place. If newline is any
of the other legal values, any '\n' characters written are translated
to the given string.
If closefd is False, the underlying file descriptor will be kept open
when the file is closed. This does not work when a file name is given
and must be True in that case.
A custom opener can be used by passing a callable as *opener*. The
underlying file descriptor for the file object is then obtained by
calling *opener* with (*file*, *flags*). *opener* must return an open
file descriptor (passing os.open as *opener* results in functionality
similar to passing None).
open() returns a file object whose type depends on the mode, and
through which the standard file operations such as reading and writing
are performed. When open() is used to open a file in a text mode ('w',
'r', 'wt', 'rt', etc.), it returns a TextIOWrapper. When used to open
a file in a binary mode, the returned class varies: in read binary
mode, it returns a BufferedReader; in write binary and append binary
modes, it returns a BufferedWriter, and in read/write mode, it returns
It is also possible to use a string or bytearray as a file for both
reading and writing. For strings StringIO can be used like a file
opened in a text mode, and for bytes a BytesIO can be used like a file
opened in a binary mode.
Help on built-in function max in module builtins:
max(iterable, *[, default=obj, key=func]) -> value
max(arg1, arg2, *args, *[, key=func]) -> value
With a single iterable argument, return its biggest item. The
default keyword-only argument specifies an object to return if
the provided iterable is empty.
With two or more arguments, return the largest argument.
Help on TextIOWrapper object:
| Character and line based layer over a BufferedIOBase object, buffer.
| encoding gives the name of the encoding that the stream will be
| decoded or encoded with. It defaults to locale.getpreferredencoding(False).
| errors determines the strictness of encoding and decoding (see
| help(codecs.Codec) or the documentation for codecs.register) and
| defaults to "strict".
| newline controls how line endings are handled. It can be None, '',
| '\n', '\r', and '\r\n'. It works as follows:
| * On input, if newline is None, universal newlines mode is
| enabled. Lines in the input can end in '\n', '\r', or '\r\n', and
| these are translated into '\n' before being returned to the
| caller. If it is '', universal newline mode is enabled, but line
| endings are returned to the caller untranslated. If it has any of
| the other legal values, input lines are only terminated by the given
| string, and the line ending is returned to the caller untranslated.
| * On output, if newline is None, any '\n' characters written are
| translated to the system default line separator, os.linesep. If
| newline is '' or '\n', no translation takes place. If newline is any
| of the other legal values, any '\n' characters written are translated
| to the given string.
| If line_buffering is True, a call to flush is implied when a call to
| write contains a newline character.
| Method resolution order:
| Methods defined here:
| __init__(self, /, *args, **kwargs)
| Initialize self. See help(type(self)) for accurate signature.
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
| __next__(self, /)
| Implement next(self).
| __repr__(self, /)
| Return repr(self).
| close(self, /)
| Flush and close the IO object.
| This method has no effect if the file is already closed.
| detach(self, /)
| Separate the underlying buffer from the TextIOBase and return it.
| After the underlying buffer has been detached, the TextIO is in an
| unusable state.
| fileno(self, /)
| Returns underlying file descriptor if one exists.
| OSError is raised if the IO object does not use a file descriptor.
| flush(self, /)
| Flush write buffers, if applicable.
| This is not implemented for read-only and non-blocking streams.
| isatty(self, /)
| Return whether this is an 'interactive' stream.
| Return False if it can't be determined.
| read(self, size=-1, /)
| Read at most n characters from stream.
| Read from underlying buffer until we have n characters or we hit EOF.
| If n is negative or omitted, read until EOF.
| readable(self, /)
| Return whether object was opened for reading.
| If False, read() will raise OSError.
| readline(self, size=-1, /)
| Read until newline or EOF.
| Returns an empty string if EOF is hit immediately.
| seek(self, cookie, whence=0, /)
| Change stream position.
| Change the stream position to the given byte offset. The offset is
| interpreted relative to the position indicated by whence. Values
| for whence are:
| * 0 -- start of stream (the default); offset should be zero or positive
| * 1 -- current stream position; offset may be negative
| * 2 -- end of stream; offset is usually negative
| Return the new absolute position.
| seekable(self, /)
| Return whether object supports random access.
| If False, seek(), tell() and truncate() will raise OSError.
| This method may need to do a test seek().
| tell(self, /)
| Return current stream position.
| truncate(self, pos=None, /)
| Truncate file to size bytes.
| File pointer is left unchanged. Size defaults to the current IO
| position as reported by tell(). Returns the new size.
| writable(self, /)
| Return whether object was opened for writing.
| If False, write() will raise OSError.
| write(self, text, /)
| Write string to stream.
| Returns the number of characters written (which is always equal to
| the length of the string).
| Data descriptors defined here:
| Encoding of the text stream.
| Subclasses should override.
| The error setting of the decoder or encoder.
| Subclasses should override.
| Line endings translated so far.
| Only line endings translated during reading are considered.
| Subclasses should override.
| Methods inherited from _IOBase:
| __iter__(self, /)
| Implement iter(self).
| readlines(self, hint=-1, /)
| Return a list of lines from the stream.
| hint can be specified to control the number of lines read: no more
| lines will be read if the total size (in bytes/characters) of all
| lines so far exceeds hint.
| writelines(self, lines, /)
| Data descriptors inherited from _IOBase:
Probably you guessed that if == is equalty, then != is the inequalty or not equal. In this example, we find what number divided by 2 results into 20 and the answer is 50 as you can see. Notice that normally facts in a while are the opposite of what normally we will say "a / 2 == 20" because we need that result of that expression being True for make while to run the block code again
Loops have 2 keywords that can be used inside their block, we will show it implementing a search on a list
ok, we have the item that we searched in the list but what if we want stop it if we find 30?
We see new things in these examples like the operator not that reverses the result of a boolean statement (What is True becomes False and opposite). The other thing that we see is that a string is indexable, you can access to a letter of it using  and the position.
oh, wait that problem didn't use any new keyword... but how the fuck can we do the same without grouping a piece of code in a function?
Yep, we're looking what seems a nested loop while. In these ocassion, exit the loop when we want using the condition of the first while can be tricky. As you can see, we had to put the increment of i at the beginning because we don't want increment when we detect the number with 3 and due that, we had to start with i being -1
What about i < 0? Well, you can guess that if we ask the member -1 of a list will complain, so we need to protect that incorrect access making loop before that sentence with the a[i] is evaluated. That's why i < 0 is there.
There is two quirks about the evaluation of conditionals. First is that languages will try anything to save run code. If the first condition in that sentence is True, then doesn't matter what says the other part of or and will not evaluate it (Making not evaluating that a[-1]). The second thing is that we group sentences in () to dictate the order of evaluation, first we want evaluate i < 0 and after that, what is inside ()
break to the rescue
Last example was not an easy example of how make nested loop that need exit in some point that isn't evaluable in the conditional. Fortunately, we have the keyword break which simply breaks the loop