Python Reference Sheet

Note: This list is not exhaustive. See the source links below for more details.

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Common Sequence Methods

Source: https://docs.python.org/3/library/stdtypes.html#typesseq-common

s.count(x)

Return total number of occurrences of x in s.

s.index(x[, i[, j]])

Return the index of the first occurrence of x in s (at or after index i and before index j).

Mutable Sequence Methods

Source: https://docs.python.org/3/library/stdtypes.html#typesseq-mutable

s.append(x)

Append x to the end of the sequence.

s.insert(i, x)

Insert x into s at the index given by i.

s.pop(i=-1)

Retrieve the item at i and also remove it from s.

s.remove(x)

Remove the first item from s where s[i] is equal to x.

Dictionary Methods

Source: https://docs.python.org/3/library/stdtypes.html#mapping-types-dict

dict.get(key, default=None)

Return the value for key if key is in the dictionary, else default. If default is not given, it defaults to None, so that this method never raises a KeyError.

dict.items()

Return a new view of the dictionary’s items ((key, value) pairs).

dict.keys()

Return a new view of the dictionary’s keys.

dict.pop(key[, default])

If key is in the dictionary, remove it and return its value, else return default. If default is not given and key is not in the dictionary, a KeyError is raised.

dict.values()

Return a new view of the dictionary’s values.

File Methods

Source: https://docs.python.org/3/library/io.html#io.TextIOBase

file.close()

Flush and close this stream. This method has no effect if the file is already closed. Once the file is closed, any operation on the file (e.g. reading or writing) will raise a ValueError.

file.flush()

Flush the write buffers of the stream if applicable. This does nothing for read-only and non-blocking streams.

file.read(size=-1, /)

Read and return at most size characters from the stream as a single str. If size is negative or None, reads until EOF.

file.readline(size=-1, /)

Read until newline or EOF and return a single str. If the stream is already at EOF, an empty string is returned. If size is specified, at most size characters will be read.

file.readlines(hint=-1, /)

Read and 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.

file.write(s, /)

Write the string s to the stream and return the number of characters written.

file.writelines(lines, /)

Write a list of lines to the stream. Line separators are not added, so it is usual for each of the lines provided to have a line separator at the end.

String Methods

Source: https://docs.python.org/3/library/stdtypes.html#string-methods

str.capitalize()

Return a copy of the string with its first character capitalized and the rest lowercased.

str.endswith(suffix[, start[, end]])

Return True if the string ends with the specified suffix, otherwise return False. suffix can also be a tuple of suffixes to look for. With optional start, test beginning at that position. With optional end, stop comparing at that position.

str.find(sub[, start[, end]])

Return the lowest index in the string where substring sub is found within the slice s[start:end]. Optional arguments start and end are interpreted as in slice notation. Return -1 if sub is not found.

str.isalpha()

Return True if all characters in the string are alphabetic and there is at least one character, False otherwise.

str.isdigit()

Return True if all characters in the string are digits and there is at least one character, False otherwise.

str.islower()

Return True if all cased characters in the string are lowercase and there is at least one cased character, False otherwise.

str.isspace()

Return True if there are only whitespace characters in the string and there is at least one character, False otherwise.

str.istitle()

Return True if the string is a titlecased string and there is at least one character, for example uppercase characters may only follow uncased characters and lowercase characters only cased ones. Return False otherwise.

str.isupper()

Return True if all cased characters in the string are uppercase and there is at least one cased character, False otherwise.

str.join(iterable)

Return a string which is the concatenation of the strings in iterable. A TypeError will be raised if there are any non-string values in iterable, including bytes objects. The separator between elements is the string providing this method.

str.lower()

Return a copy of the string with all the cased characters converted to lowercase.

str.replace(old, new, count=-1)

Return a copy of the string with all occurrences of substring old replaced by new. If count is given, only the first count occurrences are replaced. If count is not specified or -1, then all occurrences are replaced.

str.split(sep=None, maxsplit=-1)

Return a list of the words in the string, using sep as the delimiter string. If maxsplit is given, at most maxsplit splits are done (thus, the list will have at most maxsplit+1 elements). If maxsplit is not specified or -1, then there is no limit on the number of splits (all possible splits are made).

str.splitlines(keepends=False)

Return a list of the lines in the string, breaking at line boundaries. Line breaks are not included in the resulting list unless keepends is given and true.

str.startswith(prefix[, start[, end]])

Return True if string starts with the prefix, otherwise return False. prefix can also be a tuple of prefixes to look for. With optional start, test string beginning at that position. With optional end, stop comparing string at that position.

str.strip([chars])

Return a copy of the string with the leading and trailing characters removed. The chars argument is a string specifying the set of characters to be removed. If omitted or None, the chars argument defaults to removing whitespace.

str.title()

Return a titlecased version of the string where words start with an uppercase character and the remaining characters are lowercase.

str.upper()

Return a copy of the string with all the cased characters converted to uppercase.