if-statement

问题 I use the following JQ command to filter out the JSON. My requirement is to filter out the JSON message if the expected node is present. Or else, do nothing. Hence, I use if, elif, .... sed -n "s/.*Service - //p" $1/response.log* | jq "if (.requests | length) != 0 then .requests |= map(select(.id == \"123\")) elif (.result | length ) != 0 then .result |= map(select(.id== \"123\")) else " " end" > ~/result.log Looks like else is mandatory here. I dont want to do anything inside the else block.

问题 This question already has answers here : Pandas conditional creation of a series/dataframe column (8 answers) Closed 2 years ago . I'm trying to apply an if condition over a dataframe, but I'm missing something (error: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().) raw_data = {'age1': [23,45,21],'age2': [10,20,50]} df = pd.DataFrame(raw_data, columns = ['age1','age2']) def my_fun (var1,var2,var3): if (df[var1]-df[var2])>0 : df[var3]=df[var1]-df

问题 This question already has answers here : Pandas conditional creation of a series/dataframe column (8 answers) Closed 2 years ago . I'm trying to apply an if condition over a dataframe, but I'm missing something (error: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().) raw_data = {'age1': [23,45,21],'age2': [10,20,50]} df = pd.DataFrame(raw_data, columns = ['age1','age2']) def my_fun (var1,var2,var3): if (df[var1]-df[var2])>0 : df[var3]=df[var1]-df

问题 I was wondering why you would use an else if statement, and not multiple if statements? For example, what's the difference between doing this: if(i == 0) ... else if(i == 1) ... else if(i == 2) ... And this: if(i == 0) ... if(i == 1) ... if(i == 2) ... They seem to do the exact same thing. 回答1: if(i == 0) ... //if i = 0 this will work and skip following statement else if(i == 1) ...//if i not equal to 0 and if i = 1 this will work and skip following statement else if(i == 2) ...// if i not

问题 Let's try to run the following code: #include <stdio.h> #define MY_MACRO1(isArray,y) do { \ if(isArray) \ printf("%d", y[0]); \ else \ printf("%d", y); \ }while(0) int main() { int a = 38; int b[]={42}; MY_MACRO1(0,a); return 0; } it returns the error: main.c: In function ‘main’: main.c:12:39: error: subscripted value is neither array nor pointer nor vector printf("%d", y[0]); \ Ok, so we would need a #if statement to run y[0] only if the variable is an array: #define MY_MACRO2(isArray,y) do

问题 Let's try to run the following code: #include <stdio.h> #define MY_MACRO1(isArray,y) do { \ if(isArray) \ printf("%d", y[0]); \ else \ printf("%d", y); \ }while(0) int main() { int a = 38; int b[]={42}; MY_MACRO1(0,a); return 0; } it returns the error: main.c: In function ‘main’: main.c:12:39: error: subscripted value is neither array nor pointer nor vector printf("%d", y[0]); \ Ok, so we would need a #if statement to run y[0] only if the variable is an array: #define MY_MACRO2(isArray,y) do

问题 I'm programming in java and I happened to find myself with this: if(nodo == null) return null; else if(nodo.izquierda!=null && nodo.derecha==null) return nodo.izquierda; else if(nodo.izquierda==null && nodo.derecha!=null) return nodo.derecha; else return null; // si ambos hijos son nulos o no nulos My question is: Is it the same to write that as: if(nodo == null) return null; else { if(nodo.izquierda!=null && nodo.derecha==null) return nodo.izquierda; else { if(nodo.izquierda==null && nodo

问题 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 7 years ago . Can someone explain why the else: pass shown below is needed in order for the rest of the code (the final print 'processing... statement) to be executed?

问题 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 7 years ago . Can someone explain why the else: pass shown below is needed in order for the rest of the code (the final print 'processing... statement) to be executed?

问题 I am trying to sneak in an if statement within a loop for a jinja template: </table> <class="container"> <table border ="1"> <caption> BBOXX <caption> <thead class="thead-inverse"> <tr> <th>CU Serial</th> <th>System</th> <th>Version</th> <th>Enable Status</th> </tr> {% for d in client_data %} <tr> <td>{{ d["serial_number"]}} </td> <td>{{ d["hardware_type"]}} </td> {% if {{ d["current_enable_flag"]}} == TRUE %} <td> {{ON}} </td> {% else %} <td> {{OFF}} </td> {% endif %} </tr> {% endfor %} <