Cheatography

# Python Functions Cheat Sheet by KilGrave

Useful Python Built-in Functions

### Math Module Functions

 ceil(x) Returns the smallest integer greater than or equal to x copysi­gn(x, y) Returns x with the sign of y fabs(x) Returns the absolute value of x factor­ial(x) Returns the factorial of x floor(x) Returns the largest integer less than or equal to x fmod(x, y) Returns the remainder when x is divided by y isfini­te(x) Returns True if x is neither an infinity nor a NaN (Not a Number) isinf(x) Returns True if x is a positive or negative infinity isnan(x) Returns True if x is a NaN ldexp(x, i) Returns x (2*i) modf(x) Returns the fractional and integer parts of x exp(x) Returns e**x expm1(x) Returns e**x – 1 log(x[, base]) Returns the logarithm of x to the base (defaults to e) log2(x) Returns the base-2 logarithm of x log10(x) Returns the base-10 logarithm of x pow(x, y) Returns x raised to the power y sqrt(x) Returns the square root of x acos(x) Returns the arc cosine of x asin(x) Returns the arc sine of x atan(x) Returns the arc tangent of x atan2(y, x) Returns atan(y / x) cos(x) Returns the cosine of x hypot(x, y) Returns the Euclidean norm, sqrt(xx + yy) sin(x) Returns the sine of x tan(x) Returns the tangent of x degrees(x) Converts angle x from radians to degrees radians(x) Converts angle x from degrees to radians gamma(x) Returns the Gamma function at x lgamma(x) Returns the natural logarithm of the absolute value of the Gamma function at x pi Mathem­atical constant, the ratio of circum­ference of a circle to it's diameter (3.141­59...) e mathem­atical constant e (2.718­28...)
* import math and use math.fun()

### Sets Functions

 S.add(e) Adds the element e to the set S S1.upd­ate(S2) Adds the items specified in the set S2 to the set S1 S.remo­ve(e) Remove the element e from the set S S.pop() Removes any element from the set S S.clear() Remove all element from the set S S.copy() Creates a copy of the set S S1.uni­on(S2) Returns a set containing elements from both S1 and S2 S1.int­ers­ect­ion(S2) Returns a set containing elements common in set S1 and S2 S1.dif­fer­enc­e(S2) Returns a set containing elements in set S1 but not in S2 S1.sym­met­ric­_di­ffe­ren­ce(S2) Returns a set containing elements which are in one of the either sets S1 and S2, but not in both

### String Functions

 S.coun­t(str) Counts the number of times string str occurs in string S S.find­(str) Returns index of first occurrence of string str in string S, and -1 if str is not present int string S S.rfin­d(str) Returns index of last occurrence of string str in string S, and -1 if str is not present in string S S.capi­tal­ize() Returns a string that has first letter of the string S in uppercase and rest of the characters in lowercase S.title() Returns a string that has first letter of every word in the string S in uppercase and rest of the characters in lowercase S.lower() Returns a string that has all uppercase characters in string S converted into lowercase characters S.upper() Returns a string that has all lower characters in string S converted into uppercase characters S.swap­case() Returns a string that has all lowercase characters in string S converted into uppercase characters and vice versa S.isup­per() Returns True if all alphabets in string S are in upperc­ase­,else False S.islo­wer() Returns True if all alphabets in string S are in lowerc­ase­,else False S.isti­tle() Returns True if string S is in titlecase S.repl­ace­(st­r1,­str2) Returns a string that has every occurrence of string str1 in S replaced by with the occurrence of string str2 S.strip() Returns a string that has whites­paces in S removed from start and end S.lstrip() Returns a string that has whites­paces in S removed from start S.rstrip() Returns a string that has whites­paces in S removed from end S.spli­t(d­eli­meter) Returns a list formed by splitting the string S into various substring. The delimeter is used to mark the split points S.part­iti­on(­del­imeter) Partitions the string S into two parts base on delimeter and returns a tuple comprising of string before delimeter S.join­(se­quence) Returns a string comprising of elements of the sequence separated by delimeter S S.issp­ace() Returns True if all characters in string S comprise of whitespace characters only,i.e. ' ', '\n', '\t' else False S.isal­pha() Returns True if all characters in string S comprise of alphabets only, else False S.isdi­git() Returns True if all characters in string S comprise of digits only, else False S.isal­num() Returns True if all characters in string S comprise of alphabets and digits only, else False S.star­tsw­ith­(str) Returns True if string S starts with string str,else False S.ends­wit­h(str) Returns True if string S ends with string str,else False S.enco­de(str) Returns S in encoded format according to the given encoding scheme S.deco­de(str) Returns the decoded string S according to the given encoding scheme

### List

 L.appe­nd(e) Adds the element e to the end of the list L L.exte­nd(L2) Adds the items specified in the list L2 at the end of the list L L.remo­ve(e) Remove the element e from the list L L.pop(i) Removes the element specified at index i from the list L* L.count(e) Returns count of occurrence of element e in list L L.index(e) Returns index of element e from list L L.inse­rt(i,e) Returns element e at the index i in list L L.sort() Sorts the elements of the list L L.reve­rse() Reverses the order elements in list L

### File Handling

 open(f­ile­nam­e,mode) Open a file and store it as an object file.c­lose() Close a file which is opened file.r­ead() Read whole data from file file.r­ead­line() Read a line from file file.r­ead­lines() Read all the lines in a list from file file.w­rit­e('­data') Write data in a file
* Mode can be 'r', 'w' and 'a'