esProc
tbl.modify(2,col1*5:col1,col2+3:col2) //field value col1 recorded in Row 2 of Table Sequence tbl is changed to col1*5, and field value col2 to col2+3
tbl.modify(2:5,col1*5:col1,col2+3:col2) //Subsequent 5 Rows are modified from Row 2 in a consecutive way
//Modify the two Table sequences in the same dimension synchronously
A1=db.query(“select id,name,salary from salary order by id”)
A2=db.query(“select id,bonus from bonus order by id”)
A1.modify(1:A2,salary+bonus:salary) //A1 and A2 are sorted by id field, and bonus field value of A2 is added to the salary field of A1 in sequence
Perl
# In Perl, it is more convenient to modify the element value for 1D array, and you can directly assign a value, such as:
@a=(1,2,3);
$a[2]=$a[2]*2; # Multiply the third element value by 2
Foreach (@a){ #Loop through the array @a, and multiply each element value by 2; $_ indicates the current element
$_=$_*2;
}
map {$_=$_*2}@a; # It is also allowed to use a loop function map to multiply any element value by 2
The syntax for Loop function map is more convenient, but it only provides a loop variable $_ used to indicate the current element. No loop sequence number can be available. A variablecumulative sum must be otherwise defined if you want to perform filter operation depending on member sequence numbers, which will get you into a same awkward situation as that caused in writing the loop statements.
# 2D arrays come here as follows:
my @table=([1,”Zhang San”,3000,33],
[2,”Li Si”,5000,45],
[3,”Wang Wu”,6000,40]
);
$table[1][2]=$table[1][2]*2; # Multiply the values of Column 3 in Row 2 of 2D array @table by 2
$table[1][3]=$table[1][3]+2; #If the values of two fields are modified synchronously, two statements must be needed
# If you want to modify several rows continuously, only the loop statement is written as below:
for $i(1..5){ #Modify a queue of rows from Row 2 to Row 6
$table[$i][2]=$table[$i][2]*2;
$table[$i][3]=$table[$i][3]+2;
}
# If the two 2D tables in the same dimension and with same sequence will be modified, for example:
my @salary=([1,”Zhang San”,3000,33],
[2,”Li Si”,5000,45],
[3,”Wang Wu”,6000,40]
);
my @bonus=([1,750],
[2,800],
[3,950]
);
foreach $i(0..$#salary){ #Repeat the operation for each record, and add the values of Column 2 in the bonus to Column 3 of salary
$salary[$i][2]=$salary[$i][2]+$bonus[$i][1];
}
Python
# coding=gbk
a=[1,2,3,4]
a[2]=10 # Modify the value of individual element in 1D array
for i in range(0,len(a)): #Modify the values of all the elements in 1D array
a[i]=a[i]*3
data = [ [121.1, 0.02, 0.02],
[121.1, 0.05, 0.05],
[122.1, 0.56, 0.6],
[122.1, 3.79, 4.04],
[123.1, 93.75, 100.0],
[123.1, 0.01, 0.01],
[124.1, 0.01, 0.01],
[124.1, 1.01, 1.08],
[124.1, 0.11, 0.11],
[124.1, 0.05, 0.06],
[125.1, 0.39, 0.41],]
data[2][1]=5 #Modify the value of individual element in 2D array
for i in range(0,len(data)): #Modify the values of a column in 2D array
data[i][1]=data[i][1]*3
#Two 2D arrays are modified synchronously as below
salary=[[1,”Zhang San”,3000,33],
[2,”Li Si”,5000,45],
[3,”Wang Wu”,6000,40]]
bonus=[[1,750],
[2,800],
[3,950]]
for i in range(0,len(salary)): #Repeat the above operation for each record, the values of Column 2 in the bonus are added to Column 3 of salary
salary[i][2]= salary[i][2]+ bonus[i][1];
Loop functions for array-modification is unavailable in Python, and you need to write a loop program to achieve this action; column-based operations for 2D array can be achieved only by writing the loop codes.
R
tbl$c2=tbl$c2*5 #The value of Column c2 is modified as original value times 5
tbl [tbl$c1<5,]$c2=tbl[tbl$c1<5,]$c2+5 #The record field c2, for which c1<5 is true, is modified as original value plus 5
tbl [c(1,2,4),]$c2=tbl[c(1,2,4),]$c2+5 #The field values of Rows 1, 2 and 4 are modified
Synchronous modification for two data frames is not directly supported, which needs to be achieved by coding.
