Interviewer: says a couple of php functions, and i'm glad i saw this before the interview

Preface: php is a universal open-source script language, with functions encountered both during development and interview. Let's organize the usual functions today。

String (string) function

Strlen: get string length, byte length
substr count: calculate the number of times a substring appears in a string
substr: string interception, acquisition of string (by bytes interception)
strchr: similar to substr, intercepting from the given position until the end
strarchr (retrieving file suffix): as with strachr, only search for words from the right arguments
strtolocker: all characters are lowercase (for letters)
strtoupper: all characters capitalise
strev: invert string (english only: only one byte stored in english) bytes
strpos: find the place where the corresponding characters appear from the string (numeric subscript), start from the leftmost
strrpos: just start with the right of the string, like stpos. Find
trim: remove the characters on both sides of the function, default space
the st spit function divides a string into an array. Chunk spit: split the string into a series of smaller parts
st repeat: number of times a string is repeated
st replace: replace some characters in a string (case sensitive)
ucfirst: convert the first character of a string to the big write

Date(date) function

Time: returns the unix time stamp of the current time
date: format local dates and times
strtotime: parsing date or time description of any english text as unix timetamp
microtime: returns the microseconds of the current unix time stamp

Number (math) function

Abs: absolute value
floor: down
ceil: lift up
rounded
rand: get a random integer within a specified range
mt rand: get a random integer within a specified range (more efficient)
min: returns the smallest value in an array, or the smallest of several specified values
max: returns the maximum value in an array, or the maximum value in several specified values

Array function

Count: returns the number of elements in the array
key: key taken from associated arrays first name
current: the value of the current pointer obtained to point the element
next: fetch the value of the next element and move the pointer down
prev: fetch the value of the previous element and move the pointer up
end: move the pointer to the last element of the array and return the value of the final pointer position
reset: move the pointer to the first element of the array and return the value of the final pointer position
aray keys: fetch all key names of an array and return an index number group
aray values: fetch all values of an array and return an index number group
explode: break strings group
implode: returns a string of array elements
aliases for join: implode()
aray merge: group one or more numbers into one number group
aray reverse: returns the number inverted group
array flip: exchange keys and values in arrays
array ship: elements ejected from the front of arrays, value of elements obtained
aray pop: eject elements from behind arrays to obtain value of elements
aray unshift: pressing elements in front of arrays to get the number of current array elements
aray push: pressing elements from behind the array to get the number of elements of the current array

Adjudication functions

Is bool: to determine whether it's a boolean type
is float: to determine whether it's floating
is integer: to determine whether or not it's integer
is object: to determine whether or not it is an object
is array
is string: to determine whether it is a string
is resource: to determine whether it's a resource
is null: test for null
is numeric: a string of numbers or pure numbers
issue: determine whether or not to be defined

Summary

The functions listed above are only a common part of the curriculum, and interested friends can search for the "republishing academy" to see the relevant php courses。

I am a small program software developer who shares every day the knowledge points encountered in the development process, and if it helps you, i thank you very much。

(the applet has been added here, please view the front page of today)